An original Thinka practice paper modelled on the structure and difficulty of the Jun 2024 Pearson Edexcel GCSE Mathematics (1MA1) paper. Not affiliated with or reproduced from Pearson.
Paper 1 (Non-Calculator)
Answer all questions. You must show all your working. Calculators may not be used.
28 PastPaper.question · 80 PastPaper.marks
PastPaper.question 1 · Short Answer
1 PastPaper.marks
Work out \( 0.3 \times 0.06 \)
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PastPaper.workedSolution
To work out \( 0.3 \times 0.06 \), first calculate \( 3 \times 6 = 18 \). Since there are three decimal places in total in the numbers being multiplied, the final answer is \( 0.018 \).
PastPaper.markingScheme
B1 for 0.018 (or equivalent fraction, e.g. \(\frac{9}{500}\))
PastPaper.question 2 · Short Answer
1 PastPaper.marks
Simplify \( 5a \times 3b \)
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PastPaper.workedSolution
Multiply the coefficients: \( 5 \times 3 = 15 \). Then multiply the variables: \( a \times b = ab \). Combine these to get \( 15ab \).
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B1 for 15ab (or equivalent, such as 15ba)
PastPaper.question 3 · Short Answer
1 PastPaper.marks
Write the ratio \( 18 : 30 \) in its simplest form.
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PastPaper.workedSolution
Find the highest common factor of 18 and 30, which is 6. Divide both numbers in the ratio by 6: \( 18 \div 6 = 3 \) and \( 30 \div 6 = 5 \). The simplest form is \( 3:5 \).
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B1 for 3:5 (or 3 to 5)
PastPaper.question 4 · Short Answer
1 PastPaper.marks
Convert \( 4.2 \text{ litres} \) into millilitres.
A fair ordinary 6-sided dice is rolled. What is the probability of rolling a prime number? Give your answer as a fraction in its simplest form.
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PastPaper.workedSolution
The possible outcomes are 1, 2, 3, 4, 5, and 6. The prime numbers are 2, 3, and 5. There are 3 prime numbers. The probability is \( \frac{3}{6} \), which simplifies to \( \frac{1}{2} \).
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B1 for 1/2
PastPaper.question 6 · Short Answer
1 PastPaper.marks
Find the range of these numbers: \( 4, 11, 3, 9, 15, 7 \)
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PastPaper.workedSolution
The range is the difference between the largest number and the smallest number. The largest number is 15 and the smallest number is 3. \( 15 - 3 = 12 \).
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B1 for 12
PastPaper.question 7 · Short Answer
1 PastPaper.marks
Write \( 0.00073 \) in standard form.
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PastPaper.workedSolution
To write \( 0.00073 \) in standard form, move the decimal point 4 places to the right to obtain \( 7.3 \). This gives a power of \( 10^{-4} \). The standard form is \( 7.3 \times 10^{-4} \).
PastPaper.markingScheme
B1 for 7.3 x 10^-4 (accept \( 7.3 \times 10^{-4} \))
PastPaper.question 8 · Short Answer
1 PastPaper.marks
Simplify \( (y^4)^5 \)
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PastPaper.workedSolution
Using the power rule of indices, multiply the exponents: \( 4 \times 5 = 20 \). Therefore, \( (y^4)^5 = y^{20} \).
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B1 for y^20
PastPaper.question 9 · Short Answer
1 PastPaper.marks
Write \( 0.00045 \) in standard form.
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PastPaper.workedSolution
To write a number in standard form, it must be in the form \( a \times 10^n \) where \( 1 \le a < 10 \) and \( n \) is an integer. For \( 0.00045 \), we move the decimal point 4 places to the right to get \( 4.5 \). Since we moved the decimal point to the right, the index is negative: \( -4 \). Therefore, the number in standard form is \( 4.5 \times 10^{-4} \).
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B1 for \( 4.5 \times 10^{-4} \)
PastPaper.question 10 · Short Answer
1 PastPaper.marks
Simplify \( y^5 \times y^3 \).
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PastPaper.workedSolution
When multiplying terms with the same base, we add the indices: \( y^5 \times y^3 = y^{5 + 3} = y^8 \).
PastPaper.markingScheme
B1 for \( y^8 \)
PastPaper.question 11 · Structured Problem Solving
3 PastPaper.marks
Work out \( 1 \frac{3}{4} \div 2 \frac{5}{8} + \frac{1}{6} \). Give your answer as a fraction in its simplest form.
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PastPaper.workedSolution
First, convert the mixed numbers to improper fractions: \( 1 \frac{3}{4} = \frac{7}{4} \) \( 2 \frac{5}{8} = \frac{21}{8} \)
Next, perform the division of the two fractions: \( \frac{7}{4} \div \frac{21}{8} = \frac{7}{4} \times \frac{8}{21} \)
Finally, add \( \frac{1}{6} \) to the result: \( \frac{2}{3} + \frac{1}{6} = \frac{4}{6} + \frac{1}{6} = \frac{5}{6} \)
PastPaper.markingScheme
M1: Convert both mixed numbers correctly to improper fractions: \( \frac{7}{4} \) and \( \frac{21}{8} \) M1: Apply the correct method for division, e.g., \( \frac{7}{4} \times \frac{8}{21} \), to obtain \( \frac{2}{3} \) (or equivalent) A1: \( \frac{5}{6} \) oe
PastPaper.question 12 · Structured Problem Solving
3 PastPaper.marks
In a fruit bowl, the ratio of the number of apples to the number of bananas is \( 2 : 3 \). The ratio of the number of bananas to the number of oranges is \( 4 : 5 \). Find the fraction of the fruit in the bowl that are bananas. Give your fraction in its simplest form.
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PastPaper.workedSolution
Let \( A \) be the number of apples, \( B \) be the number of bananas, and \( O \) be the number of oranges. We are given: \( A : B = 2 : 3 \) \( B : O = 4 : 5 \)
To combine these ratios, find a common multiple for the term representing bananas (\( B \)), which is the lowest common multiple of 3 and 4, i.e., 12.
Scale the first ratio \( A : B \) by multiplying by 4: \( A : B = 8 : 12 \)
Scale the second ratio \( B : O \) by multiplying by 3: \( B : O = 12 : 15 \)
Combining these gives the ratio: \( A : B : O = 8 : 12 : 15 \)
Now, calculate the total number of parts in the ratio: \( 8 + 12 + 15 = 35 \)
The fraction of bananas in the fruit bowl is: \( \frac{12}{35} \)
PastPaper.markingScheme
M1: Find a common ratio scaling for B (e.g., scaling \( 2:3 \) to \( 8:12 \) or \( 4:5 \) to \( 12:15 \)) M1: Obtain a combined ratio for all three fruits: \( 8 : 12 : 15 \) (or equivalent ratio) or find the total parts of 35 A1: \( \frac{12}{35} \) oe
PastPaper.question 13 · Structured Problem Solving
3 PastPaper.marks
An isosceles triangle has side lengths \( 2x + 3 \) cm, \( 3x - 1 \) cm, and \( x + 5 \) cm. The two equal sides of the triangle are \( 2x + 3 \) cm and \( 3x - 1 \) cm. Work out the perimeter of the triangle.
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PastPaper.workedSolution
Since the two equal sides are \( 2x + 3 \) and \( 3x - 1 \), we can set up the equation: \( 2x + 3 = 3x - 1 \)
Subtract \( 2x \) from both sides: \( 3 = x - 1 \)
Add 1 to both sides: \( x = 4 \)
Now, substitute \( x = 4 \) to find the length of each side: Side 1: \( 2(4) + 3 = 11 \) cm Side 2: \( 3(4) - 1 = 11 \) cm Side 3: \( 4 + 5 = 9 \) cm
Calculate the perimeter by adding all three sides together: Perimeter = \( 11 + 11 + 9 = 31 \) cm
PastPaper.markingScheme
M1: Set up the correct algebraic equation: \( 2x + 3 = 3x - 1 \) M1: Solve to find \( x = 4 \) and substitute into at least one expression to find a side length (e.g., 11 or 9) A1: 31 (accept 31 cm)
PastPaper.question 14 · Structured Problem Solving
3 PastPaper.marks
The parallel sides of a trapezium have lengths 6 cm and 10 cm. The perpendicular height of the trapezium is \( h \) cm. A rectangle has length 12 cm and width 5 cm. The area of the trapezium is 1.2 times the area of the rectangle. Work out the value of \( h \).
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PastPaper.workedSolution
First, calculate the area of the rectangle: Area of rectangle = \( 12 \times 5 = 60 \text{ cm}^2 \)
Next, calculate the area of the trapezium: Area of trapezium = \( 1.2 \times 60 = 72 \text{ cm}^2 \)
The formula for the area of a trapezium is \( \frac{1}{2}(a + b)h \): \( \frac{1}{2}(6 + 10)h = 72 \) \( \frac{1}{2}(16)h = 72 \) \( 8h = 72 \)
Solve for \( h \): \( h = \frac{72}{8} = 9 \)
PastPaper.markingScheme
M1: Calculate the area of the rectangle: \( 12 \times 5 = 60 \) (or write an expression for the trapezium's area, e.g. \( 8h \)) M1: Form the equation \( 8h = 1.2 \times 60 \) or \( 8h = 72 \) A1: 9
PastPaper.question 15 · Structured Problem Solving
3 PastPaper.marks
There are only red counters, blue counters and green counters in a bag. The probability of picking a red counter is 0.35. The ratio of the number of blue counters to the number of green counters is 2 : 3. A counter is chosen at random from the bag. Work out the probability that the counter is green.
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PastPaper.workedSolution
The sum of all probabilities is 1. Therefore, the probability of selecting either a blue or a green counter is: \( 1 - 0.35 = 0.65 \)
This probability is divided between blue and green counters in the ratio of \( 2 : 3 \). Total parts in the ratio = \( 2 + 3 = 5 \) parts.
Calculate the probability of selecting a green counter: \( P(\text{Green}) = \frac{3}{5} \times 0.65 \) \( P(\text{Green}) = 3 \times 0.13 = 0.39 \)
PastPaper.markingScheme
M1: Subtract 0.35 from 1 to find the combined probability of blue and green counters: \( 1 - 0.35 = 0.65 \) M1: Multiply the combined probability by \( \frac{3}{5} \) (e.g., \( 0.65 \div 5 \times 3 \)) A1: 0.39 (or equivalent fraction, e.g., \( \frac{39}{100} \))
PastPaper.question 16 · Structured Problem Solving
3 PastPaper.marks
A set of 5 numbers has a mean of 8. When a 6th number is added to the set, the mean of the 6 numbers is 9.5. Work out the value of the 6th number.
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PastPaper.workedSolution
First, find the total sum of the original 5 numbers: \( \text{Sum of 5 numbers} = 5 \times 8 = 40 \)
Next, find the total sum of the 6 numbers including the new number: \( \text{Sum of 6 numbers} = 6 \times 9.5 = 57 \)
The value of the 6th number is the difference between these two sums: \( \text{6th number} = 57 - 40 = 17 \)
PastPaper.markingScheme
M1: Work out the sum of the original 5 numbers: \( 5 \times 8 = 40 \) M1: Work out the sum of the 6 numbers: \( 6 \times 9.5 = 57 \) A1: 17
PastPaper.question 17 · Structured Problem Solving
3 PastPaper.marks
Write the recurring decimal \( 0.2\dot{3}\dot{6} \) as a fraction in its simplest form. You must show all your working.
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PastPaper.workedSolution
Let \( x = 0.2363636... \)
Multiply by 10 to shift the non-repeating part past the decimal point: \( 10x = 2.363636... \) [Equation 1]
Multiply by 1000 to shift one full repeating cycle past the decimal point: \( 1000x = 236.363636... \) [Equation 2]
Simplify the fraction by dividing the numerator and denominator by 9: \( x = \frac{26}{110} \)
Simplify further by dividing by 2: \( x = \frac{13}{55} \)
PastPaper.markingScheme
M1: Set up two equations to align the recurring decimal parts, e.g., \( 10x = 2.3636... \) and \( 1000x = 236.3636... \) (or equivalent) M1: Subtract equations to obtain a correct linear relation, e.g., \( 990x = 234 \) (or \( 99x = 23.4 \)) A1: \( \frac{13}{55} \) (must be in simplest form)
PastPaper.question 18 · Structured Problem Solving
Factorise the numerator: \( 2x^2 - 5x - 3 \) We look for two numbers that multiply to \( 2 \times (-3) = -6 \) and add up to \( -5 \). These numbers are \( -6 \) and \( 1 \). \( 2x^2 - 6x + x - 3 = 2x(x - 3) + 1(x - 3) = (2x + 1)(x - 3) \)
Factorise the denominator: \( x^2 - 9 \) This is a difference of two squares: \( x^2 - 9 = (x - 3)(x + 3) \)
Write the fraction with the factorised expressions and cancel the common factor \( (x - 3) \): \( \frac{(2x + 1)(x - 3)}{(x - 3)(x + 3)} = \frac{2x + 1}{x + 3} \)
PastPaper.question 19 · Structured Problem Solving
3 PastPaper.marks
A school library has books. \(\frac{3}{8}\) of the books are fiction. \(40\%\) of the remaining books are non-fiction, and the rest are reference books. There are \(45\) reference books. Work out the total number of books in the library.
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PastPaper.workedSolution
Let the total number of books be \(x\).
1. The fraction of fiction books is \(\frac{3}{8}\), so the remaining fraction is \(1 - \frac{3}{8} = \frac{5}{8}\).
2. \(40\%\) of the remaining books are non-fiction, which is \(0.40 \times \frac{5}{8}x = \frac{2}{5} \times \frac{5}{8}x = \frac{1}{4}x\).
3. The reference books represent the remaining fraction of these books: \(100\% - 40\% = 60\%\) of the remaining books. So, Reference books = \(0.60 \times \frac{5}{8}x = \frac{3}{5} \times \frac{5}{8}x = \frac{3}{8}x\).
4. We are given that there are \(45\) reference books: \(\frac{3}{8}x = 45\).
M1: For finding the remaining fraction \(\frac{5}{8}\) or for finding \(60\%\) of the remaining books, e.g. \(0.6 \times \frac{5}{8}\) M1: For setting up the equation \(\frac{3}{8}x = 45\) or an equivalent proportion (e.g. 3 parts = 45) A1: 120
PastPaper.question 20 · Structured Problem Solving
3 PastPaper.marks
A rectangle has length \(2x + 5\) cm and width \(x + 1\) cm. An equilateral triangle has side length \(x + 7\) cm. The perimeter of the rectangle is equal to the perimeter of the triangle. Find the value of \(x\).
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PastPaper.workedSolution
1. Write down an expression for the perimeter of the rectangle: \(P_{\text{rect}} = 2((2x + 5) + (x + 1)) = 2(3x + 6) = 6x + 12\).
2. Write down an expression for the perimeter of the equilateral triangle: \(P_{\text{tri}} = 3(x + 7) = 3x + 21\).
3. Set the two perimeters equal to each other: \(6x + 12 = 3x + 21\).
4. Solve for \(x\): \(3x = 9\) \(x = 3\).
PastPaper.markingScheme
M1: For a correct expression for the perimeter of the rectangle, e.g. \(2(2x + 5 + x + 1)\) or \(6x + 12\), or for the triangle, e.g. \(3(x + 7)\) or \(3x + 21\) M1: For equating the two perimeter expressions and starting to solve, e.g. \(6x + 12 = 3x + 21\) leading to \(3x = 9\) A1: 3
PastPaper.question 21 · Structured Problem Solving
3 PastPaper.marks
There are red counters, blue counters and yellow counters in a bag. The ratio of the number of red counters to the number of blue counters is \(3 : 4\). The ratio of the number of blue counters to the number of yellow counters is \(5 : 2\). There are \(49\) more red counters than yellow counters in the bag. Work out the total number of counters in the bag.
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PastPaper.workedSolution
1. Combine the two ratios by finding a common term for the blue counters (LCM of 4 and 5 is 20): Red : Blue = \(3 \times 5 : 4 \times 5 = 15 : 20\) Blue : Yellow = \(5 \times 4 : 2 \times 4 = 20 : 8\)
2. The combined ratio of Red : Blue : Yellow is \(15 : 20 : 8\).
3. Let the number of parts for red, blue, and yellow counters be \(15p\), \(20p\), and \(8p\) respectively. The difference between red and yellow counters is: \(15p - 8p = 7p\).
4. We are given that there are \(49\) more red than yellow counters, so: \(7p = 49 \implies p = 7\).
5. The total number of counters is: \(15p + 20p + 8p = 43p\). Total = \(43 \times 7 = 301\).
PastPaper.markingScheme
M1: For finding a combined ratio Red : Blue : Yellow as \(15 : 20 : 8\) (or equivalent) M1: For setting up an equation for the difference, e.g. \(15p - 8p = 49\) or \(7 \text{ parts} = 49\), and finding the value of 1 part as 7 A1: 301
PastPaper.question 22 · Structured Problem Solving
3 PastPaper.marks
A solid prism has a cross-section in the shape of a trapezium. The parallel sides of the trapezium have lengths of \(6\) cm and \(10\) cm. The perpendicular height of the trapezium is \(h\) cm. The length of the prism is \(12\) cm. Given that the volume of the prism is \(384\text{ cm}^3\), work out the value of \(h\).
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PastPaper.workedSolution
1. Write down the formula for the area of the trapezium cross-section: \(\text{Area} = \frac{1}{2}(a+b)h = \frac{1}{2}(6 + 10)h = 8h\).
2. Use the volume of a prism formula (Volume = Area of cross-section \(\times\) length): \(\text{Volume} = 8h \times 12 = 96h\).
3. Set the volume equal to \(384\): \(96h = 384\).
4. Solve for \(h\): \(h = \frac{384}{96} = 4\).
PastPaper.markingScheme
M1: For a correct expression for the area of the cross-section, e.g., \(\frac{1}{2}(6+10)h\) or \(8h\) M1: For setting up the volume equation, e.g., \(8h \times 12 = 384\) or \(96h = 384\) A1: 4
PastPaper.question 23 · Structured Problem Solving
3 PastPaper.marks
There are only red, blue, and green counters in a bag. The probability of choosing a red counter at random is \(0.3\). The probability of choosing a blue counter at random is twice the probability of choosing a green counter. There are \(14\) green counters in the bag. Work out the total number of counters in the bag.
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PastPaper.workedSolution
1. Let the probability of choosing a green counter be \(x\). Then the probability of choosing a blue counter is \(2x\).
2. The sum of the probabilities must equal 1: \(0.3 + 2x + x = 1\) \(0.3 + 3x = 1\) \(3x = 0.7\) \(x = \frac{0.7}{3} = \frac{7}{30}\). So, the probability of choosing a green counter is \(\frac{7}{30}\).
3. Let the total number of counters be \(T\). Since there are 14 green counters, we have: \(\frac{7}{30} \times T = 14\) \(T = 14 \times \frac{30}{7} = 2 \times 30 = 60\).
PastPaper.markingScheme
M1: For forming an equation for probabilities, e.g., \(0.3 + 3x = 1\), or finding the combined probability of blue and green as 0.7 M1: For finding the probability of green as \(\frac{7}{30}\) (or 0.233...) or establishing that green represents \(\frac{7}{30}\) of the total A1: 60
PastPaper.question 24 · Structured Problem Solving
3 PastPaper.marks
Five positive integers have a mode of \(6\), a median of \(8\), a mean of \(9\), and a range of \(10\). Work out the values of these five integers.
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PastPaper.workedSolution
Let the five integers in ascending order be \(a, b, c, d, e\).
1. Since the median is 8, the middle value is 8: \(c = 8\). 2. The mode is 6. Since 6 < 8, both \(a\) and \(b\) must be 6: \(a = 6, b = 6\). 3. The range is 10. Range = \(e - a = 10\). Since \(a = 6\), then \(e = 16\). 4. The mean is 9. The sum of the 5 numbers is \(5 \times 9 = 45\). Sum = \(6 + 6 + 8 + d + 16 = 36 + d = 45\). Therefore, \(d = 9\).
The five integers are 6, 6, 8, 9, 16.
PastPaper.markingScheme
M1: For using the median to find the middle number is 8 AND the mode to find the first two numbers are 6 (i.e. finding 6, 6, 8) M1: For using the range to find the largest number is 16 (6 + 10) OR setting up the sum equation \(6 + 6 + 8 + d + 16 = 45\) A1: 6, 6, 8, 9, 16 (any order, but must be these exact five numbers)
PastPaper.question 25 · Multi-Step Application
7 PastPaper.marks
A solid is made by attaching a hemisphere of radius \(r\) cm to one flat circular face of a cylinder of radius \(r\) cm and height \(h\) cm. The total volume of the solid is \(63\pi\text{ cm}^3\). The ratio of the volume of the hemisphere to the volume of the cylinder is \(2:5\). (a) Work out the value of \(r\) and the value of \(h\). (b) The solid is made of metal with a density of \(8\text{ g/cm}^3\). Work out the total mass of the solid, leaving your answer in terms of \(\pi\).
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PastPaper.workedSolution
For part (a): Since the total volume of \(63\pi\text{ cm}^3\) is divided in the ratio \(2 : 5\) between the hemisphere and the cylinder, we first find the shares. Total shares = \(2 + 5 = 7\). One share is \(\frac{63\pi}{7} = 9\pi\text{ cm}^3\). Therefore, Volume of hemisphere = \(2 \times 9\pi = 18\pi\text{ cm}^3\) and Volume of cylinder = \(5 \times 9\pi = 45\pi\text{ cm}^3\). Using the formula for the volume of a hemisphere, \(V = \frac{2}{3}\pi r^3\): \(\frac{2}{3}\pi r^3 = 18\pi \implies \frac{2}{3}r^3 = 18 \implies r^3 = 27 \implies r = 3\). Using the formula for the volume of a cylinder, \(V = \pi r^2 h\): \(\pi (3^2) h = 45\pi \implies 9\pi h = 45\pi \implies h = 5\). For part (b): Mass = Density \(\times\) Volume. Total mass = \(8 \times 63\pi = 504\pi\text{ g}\).
PastPaper.markingScheme
Part (a): M1 for dividing \(63\pi\) into the ratio \(2 : 5\) to find either \(18\pi\) or \(45\pi\). M1 for setting up \(\frac{2}{3}\pi r^3 = 18\pi\) (or equivalent). A1 for \(r = 3\). M1 for substituting their \(r\) into the cylinder volume formula: \(\pi \times 3^2 \times h = 45\pi\) (or equivalent). A1 for \(h = 5\). Part (b): M1 for calculating \(\text{mass} = 8 \times 63\pi\). A1 for \(504\pi\) (accept with or without unit \(g\)).
PastPaper.question 26 · Multi-Step Application
7 PastPaper.marks
A rectangle has width \(2x - 3\) cm and height \(x + 4\) cm. A right-angled triangle has base \(x + 2\) cm and perpendicular height \(2x + 8\) cm. The area of the rectangle is equal to the area of the right-angled triangle. (a) Show that \(x^2 - x - 20 = 0\). (b) Find the value of \(x\), justifying why any other mathematical solution is not applicable in this context. (c) A square has a perimeter equal to the perimeter of the rectangle. Work out the area of the square.
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PastPaper.workedSolution
For part (a): Area of rectangle = \((2x - 3)(x + 4) = 2x^2 + 8x - 3x - 12 = 2x^2 + 5x - 12\). Area of triangle = \(\frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2}(x + 2)(2x + 8) = (x + 2)(x + 4) = x^2 + 6x + 8\). Since the areas are equal: \(2x^2 + 5x - 12 = x^2 + 6x + 8\). Rearranging gives: \(2x^2 - x^2 + 5x - 6x - 12 - 8 = 0 \implies x^2 - x - 20 = 0\). For part (b): Solving \(x^2 - x - 20 = 0 \implies (x - 5)(x + 4) = 0\), which gives \(x = 5\) or \(x = -4\). We must reject \(x = -4\) because it results in a negative width for the rectangle: \(2(-4) - 3 = -11\) cm, and lengths must be positive. Therefore, \(x = 5\). For part (c): Substituting \(x = 5\), the rectangle width is \(2(5) - 3 = 7\) cm and the height is \(5 + 4 = 9\) cm. Perimeter of rectangle = \(2(7 + 9) = 32\) cm. Perimeter of square = \(32\) cm. Side length of square = \(\frac{32}{4} = 8\) cm. Area of square = \(8^2 = 64\text{ cm}^2\).
PastPaper.markingScheme
Part (a): M1 for expanding rectangle dimensions to get \(2x^2 + 5x - 12\) (allow one sign error). M1 for setting up the area of the triangle and simplifying to \(x^2 + 6x + 8\). A1 for equating and completing the proof to show \(x^2 - x - 20 = 0\) with no algebraic errors. Part (b): M1 for factorising to \((x - 5)(x + 4) = 0\) or identifying roots as \(5\) and \(-4\). A1 for selecting \(x = 5\) and explaining that \(x = -4\) leads to negative lengths. Part (c): M1 for finding the perimeter of the rectangle as \(32\) cm. A1 for correct area of the square as \(64\) (accept with or without unit \(\text{cm}^2\)).
PastPaper.question 27 · Multi-Step Application
7 PastPaper.marks
There are only red counters, blue counters, and green counters in a bag. The ratio of the number of red counters to the number of blue counters is \(3 : 5\). The probability of picking a green counter at random from the bag is \(\frac{1}{5\)}. Steve adds \(2\) more green counters to the bag. The probability of picking a green counter at random from the bag is now \(\frac{1}{4}\). How many counters of each colour were originally in the bag?
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PastPaper.workedSolution
Let the original number of red counters be \(3y\) and blue counters be \(5y\). This means the sum of red and blue counters is \(8y\). Let the original number of green counters be \(g\). The total number of counters is \(8y + g\). The probability of picking a green counter is \(\frac{g}{8y + g} = \frac{1}{5}\). Multiplying both sides gives \(5g = 8y + g \implies 4g = 8y \implies g = 2y\). So, the number of green counters is \(2y\), and the total number of counters initially is \(10y\). When \(2\) green counters are added: New number of green counters is \(2y + 2\). New total number of counters is \(10y + 2\). The new probability is \(\frac{2y+2}{10y+2} = \frac{1}{4}\). Cross-multiplying: \(4(2y + 2) = 10y + 2 \implies 8y + 8 = 10y + 2 \implies 2y = 6 \implies y = 3\). Substituting \(y = 3\) back into our definitions: Red counters = \(3(3) = 9\). Blue counters = \(5(3) = 15\). Green counters = \(2(3) = 6\).
PastPaper.markingScheme
M1 for expressing red as \(3y\) and blue as \(5y\) (or total red and blue as \(8y\)). M1 for setting up the equation \(\frac{g}{8y+g} = \frac{1}{5}\) (or equivalent). M1 for finding the relation \(g = 2y\) or expressing green as a fraction of the other counters. M1 for setting up the new probability fraction with the addition of 2 green counters: \(\frac{2y+2}{10y+2} = \frac{1}{4}\). M1 for algebraic manipulation to solve for their variable (e.g., cross-multiplying). A1 for finding the parameter \(y = 3\) or the original number of green counters as \(6\). A1 for the correct original numbers: \(9\) red, \(15\) blue, \(6\) green (must be clearly identified).
PastPaper.question 28 · Multi-Step Application
7 PastPaper.marks
The points \(A\) and \(B\) have coordinates \((2, 0)\) and \((6, 8)\) respectively. The line \(L_1\) passes through \(A\) and \(B\). (a) Find an equation of the line \(L_1\), giving your answer in the form \(y = mx + c\). The line \(L_2\) is the perpendicular bisector of the line segment \(AB\). (b) Find an equation of the line \(L_2\), giving your answer in the form \(ax + by + c = 0\), where \(a\), \(b\), and \(c\) are integers. The line \(L_2\) crosses the x-axis at the point \(P\) and the y-axis at the point \(Q\). (c) Find the area of the triangle \(OPQ\), where \(O\) is the origin \((0, 0)\).
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PastPaper.workedSolution
For part (a): Gradient of \(L_1 = \frac{8 - 0}{6 - 2} = \frac{8}{4} = 2\). Using \(y - y_1 = m(x - x_1)\) with point \(A(2,0)\): \(y - 0 = 2(x - 2) \implies y = 2x - 4\). For part (b): Midpoint of \(AB = \left(\frac{2+6}{2}, \frac{0+8}{2}\right) = (4, 4)\). The gradient of the perpendicular line \(L_2\) is \(-\frac{1}{2}\). Using \(y - y_1 = m_2(x - x_1)\) with midpoint \((4,4)\): \(y - 4 = -\frac{1}{2}(x - 4)\). Multiply by 2: \(2y - 8 = -x + 4\). Rearrange to the required form: \(x + 2y - 12 = 0\). For part (c): \(P\) is on the x-axis, so \(y = 0 \implies x + 2(0) - 12 = 0 \implies x = 12\). So \(P = (12, 0)\). \(Q\) is on the y-axis, so \(x = 0 \implies 0 + 2y - 12 = 0 \implies y = 6\). So \(Q = (0, 6)\). The area of triangle \(OPQ = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 12 \times 6 = 36\).
PastPaper.markingScheme
Part (a): M1 for finding the gradient as \(2\). A1 for \(y = 2x - 4\). Part (b): M1 for finding the midpoint of \(AB\) as \((4, 4)\) or finding perpendicular gradient \(-\frac{1}{2}\). M1 for substituting their midpoint and perpendicular gradient into \(y - y_1 = m(x - x_1)\) or equivalent. A1 for \(x + 2y - 12 = 0\) (or any integer multiple thereof). Part (c): M1 for finding the intercepts \(P(12, 0)\) and \(Q(0, 6)\) from their \(L_2\) equation. A1 for correct area of \(36\).
Paper 2 (Calculator)
Answer all questions. You must show all your working. Calculators may be used.
28 PastPaper.question · 80 PastPaper.marks
PastPaper.question 1 · Short Answer
1 PastPaper.marks
Write down the reciprocal of 2.5.
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PastPaper.workedSolution
The reciprocal of a number \(x\) is \(\frac{1}{x}\). The reciprocal of 2.5 is \(\frac{1}{2.5} = 0.4\).
PastPaper.markingScheme
B1 for 0.4 (or equivalent fraction such as \(\frac{2}{5}\))
PastPaper.question 2 · Short Answer
1 PastPaper.marks
Simplify \(y^6 \div y^2\).
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PastPaper.workedSolution
Using the laws of indices, \(y^a \div y^b = y^{a-b}\). Therefore, \(y^6 \div y^2 = y^{6-2} = y^4\).
PastPaper.markingScheme
B1 for \(y^4\)
PastPaper.question 3 · Short Answer
1 PastPaper.marks
Write the ratio 15 : 35 in its simplest form.
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PastPaper.workedSolution
Divide both parts of the ratio by their highest common factor, which is 5. \(15 \div 5 = 3\) and \(35 \div 5 = 7\). So the ratio in its simplest form is 3 : 7.
PastPaper.markingScheme
B1 for 3:7 (or 3 : 7)
PastPaper.question 4 · Short Answer
1 PastPaper.marks
Write down the mathematical name of a 3D shape where all 6 faces are squares.
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PastPaper.workedSolution
A 3D shape with 6 faces where all faces are identical squares is a cube.
PastPaper.markingScheme
B1 for cube
PastPaper.question 5 · Short Answer
1 PastPaper.marks
A fair 6-sided dice is rolled once. Write down the probability of rolling a prime number.
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PastPaper.workedSolution
The outcomes on a fair 6-sided dice are 1, 2, 3, 4, 5, 6. The prime numbers are 2, 3, and 5. There are 3 prime numbers out of 6 possible outcomes. Probability = \(\frac{3}{6} = 0.5\).
PastPaper.markingScheme
B1 for 0.5 or \(\frac{1}{2}\) (or equivalent fraction)
PastPaper.question 6 · Short Answer
1 PastPaper.marks
Here is a list of numbers: 3, 8, 5, 8, 2, 9. Find the mode of these numbers.
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PastPaper.workedSolution
The mode is the value that appears most frequently in the list. The number 8 appears twice, while all other numbers appear once. So the mode is 8.
PastPaper.markingScheme
B1 for 8
PastPaper.question 7 · Short Answer
1 PastPaper.marks
An object moves at a constant speed of 15 metres per second. Convert this speed into kilometres per hour.
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PastPaper.workedSolution
To convert metres per second to kilometres per hour: \(15\text{ m/s} = 15 \times 60\text{ m/min} = 900\text{ m/min}\). \(900 \times 60\text{ m/hour} = 54000\text{ m/hour}\). Divide by 1000 to convert metres to kilometres: \(54000 \div 1000 = 54\text{ km/h}\).
PastPaper.markingScheme
B1 for 54
PastPaper.question 8 · Short Answer
1 PastPaper.marks
Find the value of \(64^{\frac{2}{3}}\).
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PastPaper.workedSolution
To find the value of \(64^{\frac{2}{3}}\), first find the cube root of 64, then square the result. \(\sqrt[3]{64} = 4\). \(4^2 = 16\).
PastPaper.markingScheme
B1 for 16
PastPaper.question 9 · Structured Problem Solving
3 PastPaper.marks
Liam invests £4500 in a savings account for 3 years. The account pays compound interest at a rate of 2.3% per annum for the first two years, and 1.5% per annum for the third year. Calculate the total interest Liam has earned at the end of the 3 years. Give your answer to the nearest penny.
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PastPaper.workedSolution
First, calculate the value of the investment at the end of the second year: \(4500 \times 1.023^2 = 4709.3805\) pounds. Next, calculate the value of the investment at the end of the third year: \(4709.3805 \times 1.015 = 4780.0212075\) pounds. Now, find the total interest earned by subtracting the initial investment: \(4780.0212075 - 4500 = 280.0212075\) pounds. Rounding to the nearest penny gives £280.02.
PastPaper.markingScheme
M1 for calculating the amount after 2 years: \(4500 \times 1.023^2\) or \(4709.38\). M1 for completing the compound interest calculation: \(4709.38 \times 1.015\) (or \(4780.02\)). A1 for 280.02 (accept £280.02).
PastPaper.question 10 · Structured Problem Solving
3 PastPaper.marks
A rectangle has width \(x + 3\) cm and length \(3x - 1\) cm. An equilateral triangle has side length \(2x + 4\) cm. The perimeter of the rectangle is equal to the perimeter of the triangle. Work out the value of \(x\).
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PastPaper.workedSolution
Perimeter of the rectangle is \(2(x + 3 + 3x - 1) = 2(4x + 2) = 8x + 4\) cm. Perimeter of the equilateral triangle is \(3(2x + 4) = 6x + 12\) cm. Since the perimeters are equal, we can write: \(8x + 4 = 6x + 12\). Subtracting \(6x\) from both sides gives \(2x + 4 = 12\). Subtracting 4 from both sides gives \(2x = 8\), which simplifies to \(x = 4\).
PastPaper.markingScheme
M1 for writing a correct expression for the perimeter of the rectangle (e.g. \(8x + 4\)) or the triangle (e.g. \(6x + 12\)). M1 for equating the two perimeters and forming a correct equation: \(8x + 4 = 6x + 12\). A1 for \(x = 4\).
PastPaper.question 11 · Structured Problem Solving
3 PastPaper.marks
A, B and C share some money in the ratio \(3 : 5 : 8\). C receives £120 more than A. Work out the total amount of money they share.
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PastPaper.workedSolution
The difference between C's share and A's share is \(8 - 3 = 5\) parts. We are given that this difference is £120, so \(5\text{ parts} = 120\). This means \(1\text{ part} = 120 \div 5 = 24\) pounds. The total number of parts shared is \(3 + 5 + 8 = 16\) parts. The total amount of money shared is \(16 \times 24 = 384\) pounds.
PastPaper.markingScheme
M1 for finding the difference in parts between A and C: \(8 - 3 = 5\). M1 for calculating the value of one part: \(120 \div 5 = 24\). A1 for 384.
PastPaper.question 12 · Structured Problem Solving
3 PastPaper.marks
A prism has a cross-section in the shape of a trapezium. The parallel sides of the trapezium are \(8\text{ cm}\) and \(12\text{ cm}\), and the perpendicular distance between them is \(5\text{ cm}\). The length of the prism is \(15\text{ cm}\). The prism is made of wood with a density of \(0.8\text{ g/cm}^3\). Work out the mass of the prism.
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PastPaper.workedSolution
First, find the area of the trapezium cross-section: \(\text{Area} = \frac{1}{2}(8 + 12) \times 5 = 50\text{ cm}^2\). Next, calculate the volume of the prism: \(\text{Volume} = 50 \times 15 = 750\text{ cm}^3\). Finally, calculate the mass of the prism using its density: \(\text{Mass} = 750 \times 0.8 = 600\text{ g}\).
PastPaper.markingScheme
M1 for calculating the area of the cross-section: \(\frac{1}{2}(8+12) \times 5 = 50\). M1 for finding the volume of the prism (\(50 \times 15 = 750\)) and multiplying by the density (\(0.8\)). A1 for 600.
PastPaper.question 13 · Structured Problem Solving
3 PastPaper.marks
A bag contains only red counters, blue counters and yellow counters. The probability of picking a red counter at random is \(0.2\). The ratio of the number of blue counters to the number of yellow counters is \(5 : 3\). There are \(15\text{ yellow counters}\) in the bag. Work out the total number of counters in the bag.
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PastPaper.workedSolution
The total probability of blue and yellow counters is \(1 - 0.2 = 0.8\). The ratio of blue to yellow is \(5 : 3\), so the probability of picking a yellow counter is \(\frac{3}{8} \times 0.8 = 0.3\). Since the probability of a yellow counter is \(0.3\) and there are \(15\) yellow counters, we set up the equation: \(\frac{15}{\text{Total}} = 0.3\). Thus, \(\text{Total} = \frac{15}{0.3} = 50\).
PastPaper.markingScheme
M1 for finding the combined probability of blue and yellow counters: \(1 - 0.2 = 0.8\). M1 for finding the probability of a yellow counter: \(\frac{3}{8} \times 0.8 = 0.3\) (or equivalent method). A1 for 50.
PastPaper.question 14 · Structured Problem Solving
3 PastPaper.marks
The mean height of a group of \(12\text{ boys}\) is \(1.62\text{ metres}\). The mean height of a group of \(8\text{ girls}\) is \(1.54\text{ metres}\). Work out the mean height of all \(20\text{ children}\).
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PastPaper.workedSolution
Calculate the total height of the boys: \(12 \times 1.62 = 19.44\text{ m}\). Calculate the total height of the girls: \(8 \times 1.54 = 12.32\text{ m}\). The overall total height for all 20 children is \(19.44 + 12.32 = 31.76\text{ m}\). The mean height is \(31.76 \div 20 = 1.588\text{ m}\).
PastPaper.markingScheme
M1 for calculating the total height of either group: \(12 \times 1.62 = 19.44\) or \(8 \times 1.54 = 12.32\). M1 for adding both total heights and dividing by 20: \((19.44 + 12.32) \div 20\). A1 for 1.588.
PastPaper.question 15 · Structured Problem Solving
3 PastPaper.marks
In the diagram, \(ABC\) and \(ACD\) are triangles. Triangle \(ABC\) is right-angled at \(B\) with \(AB = 7.2\text{ cm}\) and angle \(BAC = 35^\circ\). Triangle \(ACD\) is right-angled at \(D\) with \(CD = 5.4\text{ cm}\). Calculate the length of \(AD\). Give your answer to 3 significant figures.
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PastPaper.workedSolution
In triangle \(ABC\), the hypotenuse \(AC\) can be found using cosine: \(\cos(35^\circ) = \frac{7.2}{AC}\), which gives \(AC = \frac{7.2}{\cos(35^\circ)} \approx 8.7896\text{ cm}\). In triangle \(ACD\), \(AC\) is the hypotenuse, so by Pythagoras' theorem: \(AC^2 = AD^2 + CD^2\). Rearranging gives \(AD^2 = AC^2 - CD^2 = 8.7896^2 - 5.4^2 \approx 77.2571 - 29.16 = 48.0971\). Therefore, \(AD = \sqrt{48.0971} \approx 6.9352\text{ cm}\). To 3 significant figures, this is \(6.94\text{ cm}\).
PastPaper.markingScheme
M1 for finding the length of \(AC\): \(AC = \frac{7.2}{\cos(35)}\) (or \(8.79\)). M1 for applying Pythagoras' theorem in triangle \(ACD\): \(AD = \sqrt{AC^2 - 5.4^2}\). A1 for 6.94 (accept 6.93 to 6.95).
PastPaper.question 16 · Structured Problem Solving
3 PastPaper.marks
\(y\) is inversely proportional to the square of \(x\). When \(x = 5\), \(y = 12\). Work out the value of \(y\) when \(x = 2.5\).
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PastPaper.workedSolution
Since \(y\) is inversely proportional to \(x^2\), we can write the equation: \(y = \frac{k}{x^2}\). Substitute \(x = 5\) and \(y = 12\) to find \(k\): \(12 = \frac{k}{5^2} \implies k = 12 \times 25 = 300\). When \(x = 2.5\), calculate \(y\): \(y = \frac{300}{2.5^2} = \frac{300}{6.25} = 48\).
PastPaper.markingScheme
M1 for setting up the proportional relationship \(y = \frac{k}{x^2}\). M1 for finding the constant of proportionality \(k = 300\). A1 for 48.
PastPaper.question 17 · Structured Problem Solving
3 PastPaper.marks
A box contains only red, blue, and green counters. The ratio of the number of red counters to the number of blue counters is 3 : 5. The ratio of the number of blue counters to the number of green counters is 4 : 3. There are 25 more blue counters than green counters in the box. Work out the total number of counters in the box.
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PastPaper.workedSolution
To find a combined ratio for Red (R), Blue (B), and Green (G), we find a common multiple for B. The ratio R : B is 3 : 5, and B : G is 4 : 3. The lowest common multiple of 5 and 4 is 20. Multiplying R : B by 4 gives 12 : 20. Multiplying B : G by 5 gives 20 : 15. Thus, the combined ratio R : B : G is 12 : 20 : 15. The difference in parts between blue and green counters is \(20 - 15 = 5\) parts. We are given that this difference represents 25 counters. Therefore, 1 part represents \(25 \div 5 = 5\) counters. The total number of parts is \(12 + 20 + 15 = 47\) parts. The total number of counters is \(47 \times 5 = 235\).
PastPaper.markingScheme
M1: For a process to find a combined ratio for R : B : G, e.g., finding a common multiple for B to get \(12 : 20 : 15\). M1: For a process to find the value of one share, e.g., \(25 \div (20 - 15)\). A1: For 235.
PastPaper.question 18 · Structured Problem Solving
3 PastPaper.marks
A rectangular lawn measures 12 m by 8 m. A circular flower bed of diameter 3.5 m is created in the lawn. The rest of the lawn is covered with grass. One box of grass seed covers 6 m² of lawn and costs £4.50. Work out the total cost to buy enough boxes of grass seed to cover the lawn. You must buy whole boxes of grass seed.
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PastPaper.workedSolution
First, calculate the area of the rectangular lawn: \(\text{Area} = 12 \times 8 = 96\text{ m}^2\). Next, calculate the area of the circular flower bed. The radius is \(3.5 \div 2 = 1.75\text{ m}\). \(\text{Area of circle} = \pi \times 1.75^2 \approx 9.621\text{ m}^2\). The remaining grass area is \(96 - 9.621 = 86.379\text{ m}^2\). Find the number of boxes of seed required: \(86.379 \div 6 \approx 14.397\) boxes. Since we must buy whole boxes, we round up to 15 boxes. Finally, calculate the total cost: \(15 \times £4.50 = £67.50\).
PastPaper.markingScheme
M1: For a complete method to find the remaining grass area, e.g., \(12 \times 8 - \pi \times 1.75^2\) (yielding a value in the range 86.3 to 86.4). M1: For dividing their grass area by 6 and rounding up to the next integer to find the number of boxes (15 boxes). A1: For £67.50.
PastPaper.question 19 · Structured Problem Solving
3 PastPaper.marks
A rectangle has length \(3x + 5\) cm and width \(2x - 1\) cm. The perimeter of the rectangle is 48 cm. Work out the area of the rectangle.
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PastPaper.workedSolution
The perimeter of a rectangle is the sum of all four sides: \(2(3x + 5) + 2(2x - 1) = 48\). Expanding the brackets gives \(6x + 10 + 4x - 2 = 48\). Simplifying gives \(10x + 8 = 48\). Subtracting 8 from both sides gives \(10x = 40\), so \(x = 4\). Now, substitute \(x = 4\) to find the dimensions of the rectangle: \(\text{Length} = 3(4) + 5 = 17\text{ cm}\), and \(\text{Width} = 2(4) - 1 = 7\text{ cm}\). The area is \(\text{Length} \times \text{Width} = 17 \times 7 = 119\text{ cm}^2\).
PastPaper.markingScheme
M1: For setting up and simplifying a perimeter equation, e.g., \(2(3x + 5) + 2(2x - 1) = 48\) leading to \(10x + 8 = 48\). M1: For solving to find \(x = 4\) and substituting to find length (17) and width (7). A1: For 119.
PastPaper.question 20 · Structured Problem Solving
3 PastPaper.marks
In a group of 80 students, 45 study History, 40 study Geography, and 12 study neither. A student is chosen at random from the group. Find the probability that this student studies both History and Geography.
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PastPaper.workedSolution
The total number of students studying at least one of the two subjects is \(80 - 12 = 68\). Let \(H\) be the set of students studying History and \(G\) be the set of students studying Geography. We use the formula \(n(H \cup G) = n(H) + n(G) - n(H \cap G)\). Substituting the known values: \(68 = 45 + 40 - n(H \cap G)\), which simplifies to \(68 = 85 - n(H \cap G)\). Therefore, \(n(H \cap G) = 85 - 68 = 17\) students study both. The probability of choosing a student who studies both is \(\frac{17}{80}\) (or 0.2125).
PastPaper.markingScheme
M1: For subtracting the students who study neither from the total: \(80 - 12 = 68\). M1: For calculating the number of students who study both: \(45 + 40 - 68 = 17\). A1: For \(\frac{17}{80}\) or \(0.2125\).
PastPaper.question 21 · Structured Problem Solving
3 PastPaper.marks
A company's market value increased by 12% in 2021. In 2022, its value decreased by 5%. At the end of 2022, the company was worth £319,200. Work out the value of the company at the start of 2021.
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PastPaper.workedSolution
Let \(V\) be the initial value of the company at the start of 2021. The multiplier for a 12% increase is 1.12. The multiplier for a 5% decrease is 0.95. The equation representing the changes is \(V \times 1.12 \times 0.95 = 319200\). Combining the multipliers gives \(1.12 \times 0.95 = 1.064\). So, \(1.064V = 319200\). Solving for \(V\) gives \(V = 319200 \div 1.064 = 300000\).
PastPaper.markingScheme
M1: For identifying both multipliers as 1.12 and 0.95, or combining them to get 1.064. M1: For setting up the reverse percentage process, e.g., \(319200 \div 1.064\). A1: For 300000.
PastPaper.question 22 · Structured Problem Solving
3 PastPaper.marks
The table shows information about the heights, in cm, of 25 plants. Work out an estimate for the mean height of these plants.
First, find the midpoint of each interval: 135, 145, 155, and 165. Next, multiply each midpoint by its corresponding frequency: \(135 \times 4 = 540\), \(145 \times 9 = 1305\), \(155 \times 8 = 1240\), and \(165 \times 4 = 660\). Sum these products to find the total estimated height: \(540 + 1305 + 1240 + 660 = 3745\). Divide this total by the sum of the frequencies (25) to find the estimated mean: \(3745 \div 25 = 149.8\) cm.
PastPaper.markingScheme
M1: For finding the midpoints of the intervals (at least three correct) or showing the products of midpoints and frequencies. M1: For dividing the sum of their products \(\sum f x\) by the sum of frequencies (25). A1: For 149.8.
PastPaper.question 23 · Structured Problem Solving
3 PastPaper.marks
A pipe is used to fill a cylindrical water tank with a radius of 1.2 m. It takes 4 hours to fill the tank to a constant depth of 1.5 m. Work out the rate at which water flows through the pipe, in litres per minute. Give your answer to 3 significant figures. (Recall: \(1\text{ m}^3 = 1000\text{ litres}\)).
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PastPaper.workedSolution
First, calculate the volume of water in the tank: \(V = \pi \times r^2 \times h = \pi \times 1.2^2 \times 1.5 = 2.16\pi \approx 6.78584\text{ m}^3\). Next, convert this volume to litres: \(6.78584 \times 1000 \approx 6785.84\text{ litres}\). Calculate the total time in minutes: \(4\text{ hours} = 4 \times 60 = 240\text{ minutes}\). Find the rate of flow in litres per minute: \(6785.84 \div 240 \approx 28.274\text{ litres/minute}\). To 3 significant figures, this is 28.3.
PastPaper.markingScheme
M1: For calculating the volume of water in \(\text{m}^3\), e.g., \(\pi \times 1.2^2 \times 1.5\) (approx. 6.79). M1: For converting volume to litres and dividing by the total minutes (240). A1: For 28.3 (accept 28.2 to 28.3).
PastPaper.question 24 · Structured Problem Solving
3 PastPaper.marks
Rearrange the formula \(y = \frac{3x + 2}{x - 4}\) to make \(x\) the subject.
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PastPaper.workedSolution
Multiply both sides by \(x - 4\) to clear the fraction: \(y(x - 4) = 3x + 2\). Expand the brackets: \(xy - 4y = 3x + 2\). Group all terms containing \(x\) on one side and the other terms on the opposite side: \(xy - 3x = 4y + 2\). Factorise \(x\) from the left side: \(x(y - 3) = 4y + 2\). Finally, divide by \(y - 3\) to isolate \(x\): \(x = \frac{4y + 2}{y - 3}\).
PastPaper.markingScheme
M1: For multiplying by \(x-4\) and expanding the left-hand side: \(xy - 4y = 3x + 2\). M1: For isolating terms in \(x\) on one side and factorising: \(x(y - 3) = 4y + 2\). A1: For \(x = \frac{4y + 2}{y - 3}\) (or equivalent expression, e.g., \(x = \frac{-4y - 2}{3 - y}\)).
PastPaper.question 25 · Multi-Step Application
6 PastPaper.marks
A company manufactures metal paperweights. Each paperweight is in the shape of a cylinder of radius \(3\text{ cm}\) and height \(8\text{ cm}\). The paperweight is made of a metal alloy with a density of \(7.8\text{ g/cm}^3\). The company makes 250 of these paperweights. The metal alloy costs \(£4.20\) per kg. There is a manufacturing waste of 5% of the total metal alloy ordered (meaning they must buy 5% more metal than the total weight of the 250 finished paperweights). Calculate the total cost of the metal alloy needed to make the 250 paperweights. Give your answer to the nearest penny.
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PastPaper.workedSolution
1. Volume of one cylinder: \(V = \pi r^2 h = \pi \times 3^2 \times 8 = 72\pi \approx 226.1947\text{ cm}^3\). 2. Total volume of 250 cylinders: \(250 \times 72\pi = 18000\pi \approx 56548.6678\text{ cm}^3\). 3. Total mass of 250 cylinders: \(\text{Mass} = \text{Volume} \times \text{Density} = 56548.6678 \times 7.8 = 441079.6087\text{ g}\). 4. Convert mass to kg: \(441.0796087\text{ kg}\). 5. Total mass to order including 5% waste: \(441.0796087 \times 1.05 = 463.133589\text{ kg}\). 6. Total cost: \(463.133589 \times 4.20 = 1945.16107\) which rounds to \(£1945.16\).
PastPaper.markingScheme
M1: for attempting to find the volume of one cylinder: \(\pi \times 3^2 \times 8\) or \(72\pi\). M1: for multiplying by 250 and then by 7.8 to find the total mass in grams (approx. 441080 g). M1: for dividing the mass by 1000 to convert to kg (approx. 441.1 kg). M1: for accounting for the 5% waste by multiplying by 1.05 (approx. 463.1 kg). M1: for multiplying the mass in kg by 4.20. A1: for the correct final cost of £1945.16 (accept £1945.16 to £1945.17 depending on rounding methods).
PastPaper.question 26 · Multi-Step Application
6 PastPaper.marks
A rectangular lawn has length \((2x + 5)\text{ m}\) and width \((x + 3)\text{ m}\). Inside the lawn, there is a square flower bed of side length \((x - 1)\text{ m}\). The remaining area of the lawn (excluding the flower bed) is \(115\text{ m}^2\). Calculate the perimeter of the outer rectangular lawn. Show your working clearly and give your answer to 3 significant figures.
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PastPaper.workedSolution
1. Area of the outer rectangle: \((2x + 5)(x + 3) = 2x^2 + 11x + 15\). 2. Area of the square flower bed: \((x - 1)^2 = x^2 - 2x + 1\). 3. Set up the equation for the remaining area: \((2x^2 + 11x + 15) - (x^2 - 2x + 1) = 115\). Simplifying this gives \(x^2 + 13x + 14 = 115\), which rearranges to \(x^2 + 13x - 101 = 0\). 4. Solve the quadratic equation using the quadratic formula: \(x = \frac{-13 \pm \sqrt{13^2 - 4(1)(-101)}}{2} = \frac{-13 \pm \sqrt{169 + 404}}{2} = \frac{-13 \pm \sqrt{573}}{2}\). Since \(x > 1\), we choose the positive root: \(x = \frac{-13 + 23.9374}{2} \approx 5.4687\text{ m}\). 5. Perimeter of the outer lawn: \(P = 2((2x + 5) + (x + 3)) = 2(3x + 8) = 6x + 16\). Substituting \(x \approx 5.4687\): \(P = 6(5.4687) + 16 \approx 48.8122\text{ m}\). To 3 significant figures, the perimeter is \(48.8\text{ m}\).
PastPaper.markingScheme
M1: for expansion of rectangular area as \(2x^2 + 11x + 15\). M1: for expansion of square area as \(x^2 - 2x + 1\). M1: for setting up the simplified quadratic equation \(x^2 + 13x - 101 = 0\). M1: for solving the quadratic equation to find \(x \approx 5.47\) (ignoring negative root). M1: for substituting their positive \(x\) into the expression for the perimeter, \(2(3x + 8)\) or \(6x + 16\). A1: for the correct perimeter of \(48.8\text{ m}\) (accept \(48.8\) or \(48.81\)).
PastPaper.question 27 · Multi-Step Application
6 PastPaper.marks
There are some green, red, and blue counters in a bag. The ratio of the number of green counters to the number of red counters is \(3 : 4\). The probability of choosing a blue counter at random from the bag is \(\frac{1}{5}\). Two counters are taken at random from the bag without replacement. The probability that both counters are green is \(\frac{4}{35}\). Find the total number of counters in the bag.
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PastPaper.workedSolution
1. Let the number of green counters be \(3x\) and red counters be \(4x\). The combined number of green and red counters is \(7x\). 2. Since the probability of choosing a blue counter is \(\frac{1}{5}\), the probability of choosing a non-blue counter (green or red) is \(\frac{4}{5}\). This means \(\frac{7x}{\text{Total}} = \frac{4}{5}\), so \(\text{Total} = \frac{35x}{4}\). 3. To work with integers, let \(x = 4k\). This gives: Green = \(12k\), Red = \(16k\), and Total = \(35k\). 4. The probability of picking two green counters without replacement is: \(P(G, G) = \frac{12k}{35k} \times \frac{12k - 1}{35k - 1} = \frac{12}{35} \times \frac{12k - 1}{35k - 1}\). 5. Set this equal to \(\frac{4}{35}\): \(\frac{12}{35} \times \frac{12k - 1}{35k - 1} = \frac{4}{35} \implies 3 \times \frac{12k - 1}{35k - 1} = 1 \implies 36k - 3 = 35k - 1 \implies k = 2\). 6. The total number of counters is \(35k = 35 \times 2 = 70\).
PastPaper.markingScheme
M1: for establishing algebraic expressions for Green, Red, and Blue counters in terms of a single variable, e.g., Green = \(12k\), Red = \(16k\), Blue = \(7k\), Total = \(35k\). M1: for writing the correct algebraic probability for selecting two green counters without replacement: \(\frac{12k}{35k} \times \frac{12k - 1}{35k - 1}\). M1: for setting up the equation: \(\frac{12}{35} \times \frac{12k - 1}{35k - 1} = \frac{4}{35}\). M1: for simplifying the equation to a linear form, e.g., \(3(12k - 1) = 35k - 1\). M1: for solving to find \(k = 2\) (or equivalent variable). A1: for the correct total number of counters of 70.
PastPaper.question 28 · Multi-Step Application
6 PastPaper.marks
Three ports, \(A\), \(B\), and \(C\), are situated such that Port \(B\) is on a bearing of \(075^\circ\) from Port \(A\) at a distance of \(18\text{ km}\). Port \(C\) is on a bearing of \(150^\circ\) from Port \(B\) at a distance of \(25\text{ km}\). A boat sails directly from \(A\) to \(C\). Calculate the bearing of \(C\) from \(A\). Give your answer to the nearest degree.
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PastPaper.workedSolution
1. Determine the interior angle \(\angle ABC\). The bearing of \(B\) from \(A\) is \(075^\circ\), so the back-bearing of \(A\) from \(B\) is \(180^\circ + 75^\circ = 255^\circ\). The bearing of \(C\) from \(B\) is \(150^\circ\). Thus, \(\angle ABC = 255^\circ - 150^\circ = 105^\circ\). 2. Use the Cosine Rule to find distance \(AC\): \(AC^2 = 18^2 + 25^2 - 2 \times 18 \times 25 \times \cos(105^\circ) = 324 + 625 - 900(-0.258819) = 949 + 232.937 = 1181.937\). Hence, \(AC = \sqrt{1181.937} \approx 34.379\text{ km}\). 3. Use the Sine Rule to find the angle \(\angle BAC\): \(\frac{\sin(\angle BAC)}{25} = \frac{\sin(105^\circ)}{34.379} \implies \sin(\angle BAC) = \frac{25 \times \sin(105^\circ)}{34.379} \approx 0.7024\). Therefore, \(\angle BAC = \sin^{-1}(0.7024) \approx 44.62^\circ\). 4. Calculate the bearing of \(C\) from \(A\). The bearing of \(B\) from \(A\) is \(075^\circ\), so the bearing of \(C\) from \(A\) is \(075^\circ + 44.62^\circ = 119.62^\circ\). To the nearest degree, this is \(120^\circ\).
PastPaper.markingScheme
M1: for calculating the interior angle \(\angle ABC = 105^\circ\). M1: for substituting correctly into the cosine rule: \(AC^2 = 18^2 + 25^2 - 2(18)(25)\cos(105^\circ)\). A1: for finding the distance \(AC \approx 34.4\text{ km}\) (or showing \(34.379...\)). M1: for substituting correctly into the sine rule (or cosine rule) to find angle \(\angle BAC\): \(\frac{\sin(\angle BAC)}{25} = \frac{\sin(105^\circ)}{34.379}\). A1: for finding \(\angle BAC \approx 44.6^\circ\) (or \(45^\circ\)). A1: for the correct bearing of \(120^\circ\) (accept \(120\) or \(120^\circ\)).
Paper 3 (Calculator)
Answer all questions. You must show all your working. Calculators may be used.
30 PastPaper.question · 80 PastPaper.marks
PastPaper.question 1 · Short Answer
1 PastPaper.marks
Write down the value of the 7 in the number \(23.471\)
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PastPaper.workedSolution
In the number \(23.471\), the digit \(2\) is in the tens column, \(3\) is in the units column, \(4\) is in the tenths column, \(7\) is in the hundredths column, and \(1\) is in the thousandths column. Therefore, the value of the 7 is \(0.07\) (or seven hundredths).
PastPaper.markingScheme
B1 for \(0.07\) or \(\frac{7}{100}\) or seven hundredths.
PastPaper.question 2 · Short Answer
1 PastPaper.marks
Simplify \(3a \times 4b\)
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PastPaper.workedSolution
To simplify \(3a \times 4b\), multiply the coefficients and the variables: \(3 \times 4 \times a \times b = 12ab\).
PastPaper.markingScheme
B1 for \(12ab\) (accept equivalent forms like \(12ba\)).
PastPaper.question 3 · Short Answer
1 PastPaper.marks
Write the ratio \(18 : 45\) in its simplest form.
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PastPaper.workedSolution
To simplify the ratio \(18 : 45\), find the highest common factor of \(18\) and \(45\), which is \(9\). Divide both numbers by \(9\): \(18 \div 9 = 2\) and \(45 \div 9 = 5\). So, the ratio in its simplest form is \(2 : 5\).
A fair ordinary six-sided dice is rolled. Write down the probability that the dice lands on a prime number.
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PastPaper.workedSolution
The possible outcomes on a six-sided dice are \(1, 2, 3, 4, 5, 6\). The prime numbers in this set are \(2, 3,\) and \(5\). There are \(3\) prime numbers out of \(6\) outcomes in total. The probability is \(\frac{3}{6} = \frac{1}{2} = 0.5\).
PastPaper.markingScheme
B1 for \(0.5\), \(\frac{1}{2}\) or \(50\%\) (accept any equivalent fraction).
PastPaper.question 6 · Short Answer
1 PastPaper.marks
Find the median of the following list of numbers: \(12, 5, 8, 14, 9, 11, 7\).
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PastPaper.workedSolution
First, arrange the numbers in ascending order: \(5, 7, 8, 9, 11, 12, 14\). There are 7 numbers, so the median is the middle number (the 4th number), which is \(9\).
PastPaper.markingScheme
B1 for \(9\).
PastPaper.question 7 · Short Answer
1 PastPaper.marks
Write the number \(0.000038\) in standard form.
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PastPaper.workedSolution
To write \(0.000038\) in standard form, we move the decimal point 5 places to the right to get a number between 1 and 10, which is \(3.8\). Since we moved the decimal point to the right, the power of 10 is negative. Thus, the number is \(3.8 \times 10^{-5}\).
PastPaper.markingScheme
B1 for \(3.8 \times 10^{-5}\) (or equivalent).
PastPaper.question 8 · Short Answer
1 PastPaper.marks
Factorise fully \(6x^2 - 9x\).
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PastPaper.workedSolution
To factorise \(6x^2 - 9x\), we find the highest common factor of the terms \(6x^2\) and \(-9x\). The highest common factor is \(3x\). Dividing each term by \(3x\) gives \(2x - 3\). So, the factorised expression is \(3x(2x - 3)\).
PastPaper.markingScheme
B1 for \(3x(2x - 3)\).
PastPaper.question 9 · Short Answer
1 PastPaper.marks
Write the ratio \(250\text{ m}\) to \(1.25\text{ km}\) in the form \(1 : n\).
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PastPaper.workedSolution
First, convert both quantities into the same units. Since \(1\text{ km} = 1000\text{ m}\): \(1.25\text{ km} = 1.25 \times 1000\text{ m} = 1250\text{ m}\).
Now, write the ratio of the two quantities: \(250 : 1250\)
To write the ratio in the form \(1 : n\), divide both sides by \(250\): \(\frac{250}{250} : \frac{1250}{250} = 1 : 5\)
Therefore, \(n = 5\) and the ratio is \(1 : 5\).
PastPaper.markingScheme
B1: For \(1 : 5\) (accept \(n = 5\))
PastPaper.question 10 · Short Answer
1 PastPaper.marks
Write the ratio \(250\text{ m}\) to \(1.25\text{ km}\) in the form \(1 : n\).
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PastPaper.workedSolution
First, convert both quantities into the same units. Since \(1\text{ km} = 1000\text{ m}\): \(1.25\text{ km} = 1.25 \times 1000\text{ m} = 1250\text{ m}\).
Now, write the ratio of the two quantities: \(250 : 1250\)
To write the ratio in the form \(1 : n\), divide both sides by \(250\): \(\frac{250}{250} : \frac{1250}{250} = 1 : 5\)
Therefore, \(n = 5\) and the ratio is \(1 : 5\).
PastPaper.markingScheme
B1: For \(1 : 5\) (accept \(n = 5\))
PastPaper.question 11 · Structured Problem Solving
3 PastPaper.marks
A gold coin is made from an alloy of gold and copper in the ratio 11 : 1 by mass. The mass of the coin is 36 grams.
Gold costs £48 per gram. Copper costs £0.05 per gram.
Work out the total cost of the metal in the coin.
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PastPaper.workedSolution
First, find the total number of parts in the ratio: \(11 + 1 = 12\) parts.
Next, calculate the mass of one part: \(36 \div 12 = 3\) grams.
Find the mass of gold and copper in the coin: Mass of gold = \(11 \times 3 = 33\) grams. Mass of copper = \(1 \times 3 = 3\) grams.
Calculate the cost of each metal: Cost of gold = \(33 \times 48 = £1584\). Cost of copper = \(3 \times 0.05 = £0.15\).
Calculate the total cost: \(1584 + 0.15 = 1584.15\).
PastPaper.markingScheme
M1: for dividing the total mass by the sum of the ratio parts to find the unit mass, e.g. \(36 \div (11+1)\), or finding the correct mass of gold (33 g) and copper (3 g). M1: for a complete method to calculate the total cost, e.g. \((33 \times 48) + (3 \times 0.05)\). A1: for 1584.15 (accept £1584.15).
PastPaper.question 12 · Structured Problem Solving
3 PastPaper.marks
A rectangular garden has a length of 12 metres and a width of 8 metres. A circular pond of radius 2.5 metres is built in the garden. The rest of the garden is covered in grass.
Work out the area of the garden covered in grass. Give your answer correct to 3 significant figures.
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PastPaper.workedSolution
First, find the area of the rectangular garden: \(\text{Area of rectangle} = 12 \times 8 = 96\text{ m}^2\).
Next, find the area of the circular pond: \(\text{Area of circle} = \pi \times r^2 = \pi \times 2.5^2 = 6.25\pi \approx 19.635\text{ m}^2\).
Subtract the area of the pond from the area of the garden to find the grass area: \(\text{Area of grass} = 96 - 19.635 = 76.365\text{ m}^2\).
Rounding to 3 significant figures gives \(76.4\text{ m}^2\).
PastPaper.markingScheme
M1: for finding the area of the rectangle \(12 \times 8 = 96\) or the area of the circular pond \(\pi \times 2.5^2\) (implied by \(19.6\) or \(6.25\pi\)). M1: for a complete method of subtracting the area of the pond from the area of the rectangle, e.g. \(96 - \pi \times 2.5^2\). A1: for 76.4 (accept 76.3 to 76.4).
PastPaper.question 13 · Structured Problem Solving
3 PastPaper.marks
An online shop sells t-shirts. The shop charges a fixed postage fee for any order, plus a constant cost per t-shirt.
Liam buys 3 t-shirts and pays a total of £28.50. Sophia buys 7 t-shirts and pays a total of £58.50.
Work out the total cost of 5 t-shirts, including the postage fee.
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PastPaper.workedSolution
Let \(x\) be the cost of one t-shirt and \(y\) be the postage fee. From the given information, we can write two equations: 1) \(3x + y = 28.50\) 2) \(7x + y = 58.50\)
Subtract equation (1) from equation (2): \(4x = 30.00\) \(x = 7.50\) So, each t-shirt costs £7.50.
Substitute \(x = 7.50\) into equation (1) to find the postage fee: \(3(7.50) + y = 28.50\) \(22.50 + y = 28.50\) \(y = 6.00\) So, the postage fee is £6.00.
Now, work out the cost of 5 t-shirts including postage: \(5 \times 7.50 + 6.00 = 37.50 + 6.00 = 43.50\).
PastPaper.markingScheme
M1: for a correct method to find the cost of one t-shirt, e.g. \((58.50 - 28.50) \div 4\) (implied by 7.50). M1: for a method to find the postage fee, e.g. \(28.50 - 3 \times 7.50\) (implied by 6.00), or a correct expression for 5 t-shirts including postage, e.g. \(5 \times 7.50 + 6.00\). A1: for 43.50 (accept £43.50).
PastPaper.question 14 · Structured Problem Solving
3 PastPaper.marks
Daniel invests £4500 in a savings account for 3 years. The account pays compound interest at a rate of 2.4% per annum.
Calculate the total interest Daniel has earned at the end of 3 years. Give your answer to the nearest penny.
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PastPaper.workedSolution
To calculate the total amount in the account after 3 years, use the compound interest formula: \(\text{Total Amount} = 4500 \times (1 + 0.024)^3\) \(\text{Total Amount} = 4500 \times 1.024^3 = 4500 \times 1.073741824 = 4831.838208\)
To find the interest earned, subtract the original investment from the total amount: \(\text{Interest Earned} = 4831.838208 - 4500 = 331.838208\)
Rounding to the nearest penny gives \(£331.84\).
PastPaper.markingScheme
M1: for a correct method to calculate the total value of the investment after 3 years, e.g. \(4500 \times 1.024^3\) (implied by 4831.84). M1: for a method to calculate the interest by subtracting 4500 from their total value, e.g. \(4831.838... - 4500\). A1: for 331.84 (accept £331.84).
PastPaper.question 15 · Structured Problem Solving
3 PastPaper.marks
A group of 30 students took a science test. The mean mark of the 18 girls in the class was 72%. The mean mark of the 12 boys in the class was 65%.
Work out the mean mark of all 30 students.
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PastPaper.workedSolution
First, calculate the total percentage marks of all the girls: \(18 \times 72 = 1296\)
Next, calculate the total percentage marks of all the boys: \(12 \times 65 = 780\)
Find the combined total marks of all 30 students: \(1296 + 780 = 2076\)
Now, divide this total by the number of students (30) to find the mean: \(\text{Mean} = 2076 \div 30 = 69.2\).
PastPaper.markingScheme
M1: for finding the total marks for the girls, i.e. \(18 \times 72 = 1296\), or the boys, i.e. \(12 \times 65 = 780\). M1: for a complete method to find the overall mean, i.e. \((1296 + 780) \div 30\). A1: for 69.2 (accept 69.2%).
PastPaper.question 16 · Structured Problem Solving
3 PastPaper.marks
A biased four-sided spinner can land on 1, 2, 3 or 4. The table shows some of the probabilities that the spinner lands on each number.
Number | Probability 1 | 0.15 2 | 2x 3 | 0.37 4 | x
The spinner is spun 200 times. Work out an estimate for the number of times the spinner lands on 2.
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PastPaper.workedSolution
The sum of the probabilities for all possible outcomes must equal 1. Write an equation for the sum: \(0.15 + 2x + 0.37 + x = 1\)
Calculate the probability of landing on 2: \(\text{Probability} = 2x = 2 \times 0.16 = 0.32\)
To find the estimate for the number of times the spinner lands on 2 in 200 spins, multiply the probability by the total number of spins: \(\text{Estimate} = 200 \times 0.32 = 64\).
PastPaper.markingScheme
M1: for setting up a correct equation for the sum of probabilities, e.g. \(0.15 + 2x + 0.37 + x = 1\), or \(3x = 0.48\). M1: for finding \(x = 0.16\) and calculating the probability of landing on 2 as \(0.32\), then multiplying by 200. A1: for 64.
PastPaper.question 17 · Structured Problem Solving
3 PastPaper.marks
A right-angled triangle has a base of \((2x - 3)\) cm and a height of \((x + 2)\) cm. The area of the triangle is 15 cm².
Find the value of \(x\).
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PastPaper.workedSolution
The area of a triangle is given by \(\frac{1}{2} \times \text{base} \times \text{height}\). Set up the equation using the given values: \(\frac{1}{2} (2x - 3)(x + 2) = 15\)
Multiply both sides by 2: \((2x - 3)(x + 2) = 30\)
Expand the brackets: \(2x^2 + 4x - 3x - 6 = 30\) \(2x^2 + x - 6 = 30\)
Rearrange into standard quadratic form: \(2x^2 + x - 36 = 0\)
This gives two solutions for \(x\): \(x = -4.5\) or \(x = 4\).
Since \(x\) represents lengths, the side length \(2x - 3\) must be positive, which means \(x\) must be positive. Therefore, \(x = 4\).
PastPaper.markingScheme
M1: for setting up the equation for the area, e.g. \(\frac{1}{2}(2x - 3)(x + 2) = 15\) or \(2x^2 + x - 6 = 30\). M1: for a correct method to solve their quadratic equation \(2x^2 + x - 36 = 0\), e.g. by factorising to \((2x + 9)(x - 4) = 0\) or using the quadratic formula. A1: for 4 (and rejecting \(-4.5\) as a valid answer).
PastPaper.question 18 · Structured Problem Solving
3 PastPaper.marks
Liquid A has a density of 1.2 g/cm³. Liquid B has a density of 0.8 g/cm³.
250 cm³ of Liquid A is mixed with 150 cm³ of Liquid B to make Liquid C.
Work out the density of Liquid C.
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PastPaper.workedSolution
First, calculate the mass of Liquid A: \(\text{Mass} = \text{Density} \times \text{Volume}\) \(\text{Mass of A} = 1.2 \times 250 = 300\text{ g}\)
Next, calculate the mass of Liquid B: \(\text{Mass of B} = 0.8 \times 150 = 120\text{ g}\)
Calculate the total mass and total volume of Liquid C: \(\text{Total Mass} = 300 + 120 = 420\text{ g}\) \(\text{Total Volume} = 250 + 150 = 400\text{ cm}^3\)
Finally, calculate the density of Liquid C: \(\text{Density of C} = \frac{\text{Total Mass}}{\text{Total Volume}} = \frac{420}{400} = 1.05\text{ g/cm}^3\).
PastPaper.markingScheme
M1: for calculating the mass of Liquid A (\(1.2 \times 250 = 300\text{ g}\)) or the mass of Liquid B (\(0.8 \times 150 = 120\text{ g}\)). M1: for a complete method to find the density of the mixture by dividing total mass by total volume, e.g. \((300 + 120) \div (250 + 150)\). A1: for 1.05.
PastPaper.question 19 · Structured Problem Solving
3 PastPaper.marks
Metal A has a density of \(8.4\text{ g/cm}^3\). Metal B has a density of \(6.0\text{ g/cm}^3\).
An alloy is made by mixing \(150\text{ cm}^3\) of Metal A and \(250\text{ cm}^3\) of Metal B.
Calculate the density of the alloy.
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PastPaper.workedSolution
To find the density of the alloy, we need to find the total mass and divide it by the total volume.
First, calculate the mass of Metal A: \[\text{Mass of A} = \text{Density} \times \text{Volume} = 8.4\text{ g/cm}^3 \times 150\text{ cm}^3 = 1260\text{ g}\]
Next, calculate the mass of Metal B: \[\text{Mass of B} = \text{Density} \times \text{Volume} = 6.0\text{ g/cm}^3 \times 250\text{ cm}^3 = 1500\text{ g}\]
Now, find the total mass of the alloy: \[\text{Total mass} = 1260\text{ g} + 1500\text{ g} = 2760\text{ g}\]
Find the total volume of the alloy: \[\text{Total volume} = 150\text{ cm}^3 + 250\text{ cm}^3 = 400\text{ cm}^3\]
Finally, calculate the density of the alloy: \[\text{Density} = \frac{\text{Total mass}}{\text{Total volume}} = \frac{2760}{400} = 6.9\text{ g/cm}^3\]
PastPaper.markingScheme
M1: For a method to find the mass of either Metal A or Metal B (e.g. \(8.4 \times 150\) or \(6.0 \times 250\)). M1: For a complete method to find the density of the alloy, e.g. \(\frac{(8.4 \times 150) + (6.0 \times 250)}{150 + 250}\). A1: For \(6.9\) (or equivalent).
PastPaper.question 20 · Structured Problem Solving
3 PastPaper.marks
A garden bed is designed in the shape of a rectangle with a semicircle attached to one of its shorter sides.
The rectangle has a length of \(12\text{ m}\) and a width of \(5\text{ m}\). The diameter of the semicircle is equal to the width of the rectangle, as shown in the design.
Calculate the total perimeter of the garden bed. Give your answer correct to 3 significant figures.
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PastPaper.workedSolution
The perimeter of the garden bed consists of three sides of the rectangle and the curved arc of the semicircle.
First, calculate the length of the curved arc of the semicircle with diameter \(d = 5\text{ m}\): \[\text{Arc length} = \frac{1}{2} \times \pi \times d = \frac{1}{2} \times \pi \times 5 = 2.5\pi \approx 7.854\text{ m}\]
Next, sum the three straight outer edges of the rectangle (the two lengths of \(12\text{ m}\) and one width of \(5\text{ m}\)): \[\text{Straight edges} = 12 + 12 + 5 = 29\text{ m}\]
Add these together to get the total perimeter: \[\text{Total perimeter} = 29 + 7.854 = 36.854\text{ m}\]
Correct to 3 significant figures, this is \(36.9\text{ m}\).
PastPaper.markingScheme
M1: For a correct method to find the arc length of the semicircle, e.g. \(\pi \times 5 \div 2\) or \(\approx 7.85\). M1: For adding the three sides of the rectangle to their arc length, e.g. \(12 + 12 + 5 + \text{their arc length}\). A1: For an answer in the range \(36.8\) to \(37.0\) (or \(29 + 2.5\pi\)).
PastPaper.question 21 · Structured Problem Solving
3 PastPaper.marks
An isosceles triangle has side lengths of \((2x + 5)\text{ cm}\), \((2x + 5)\text{ cm}\), and \((4x - 3)\text{ cm}\).
The total perimeter of the triangle is \(47\text{ cm}\).
Work out the length of the longest side of this triangle.
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PastPaper.workedSolution
First, form an algebraic expression for the perimeter of the triangle by summing the lengths of its three sides: \[\text{Perimeter} = (2x + 5) + (2x + 5) + (4x - 3)\] \[\text{Perimeter} = 8x + 7\]
We are given that the perimeter is \(47\text{ cm}\), so we can set up the equation: \[8x + 7 = 47\] \[8x = 40\] \[x = 5\]
Now, substitute \(x = 5\) back into the side lengths to find their values: - Side 1: \(2(5) + 5 = 15\text{ cm}\) - Side 2: \(2(5) + 5 = 15\text{ cm}\) - Side 3: \(4(5) - 3 = 17\text{ cm}\)
The longest side of the triangle is \(17\text{ cm}\).
PastPaper.markingScheme
M1: For a correct expression for the perimeter, e.g., \((2x + 5) + (2x + 5) + (4x - 3)\) or \(8x + 7\). M1: (dep) For setting up and solving their equation to find \(x\), e.g., \(8x + 7 = 47\) leading to \(x = 5\). A1: For \(17\).
PastPaper.question 22 · Structured Problem Solving
3 PastPaper.marks
A biased four-sided spinner can land on Red, Blue, Yellow, or Green.
The table shows some of the probabilities of the spinner landing on each colour:
| Colour | Red | Blue | Yellow | Green | |---|---|---|---|---| | Probability | 0.35 | 0.25 | | 0.15 |
The spinner is spun 240 times.
Calculate an estimate for the number of times the spinner lands on Yellow.
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PastPaper.workedSolution
The sum of probabilities in any probability distribution is 1. First, calculate the probability of the spinner landing on Yellow: \[P(\text{Yellow}) = 1 - (0.35 + 0.25 + 0.15)\] \[P(\text{Yellow}) = 1 - 0.75 = 0.25\]
To find the expected number of times the spinner lands on Yellow, multiply this probability by the total number of spins: \[\text{Expected frequency} = 0.25 \times 240 = 60\]
PastPaper.markingScheme
M1: For a method to find the probability of landing on Yellow, e.g., \(1 - (0.35 + 0.25 + 0.15)\) or \(0.25\). M1: For a method to calculate the expected frequency, e.g., \(\text{their } P(\text{Yellow}) \times 240\). A1: For \(60\).
PastPaper.question 23 · Structured Problem Solving
3 PastPaper.marks
An athlete runs a distance of \(400\text{ m}\), correct to the nearest \(10\text{ m}\). The time taken is measured as \(52\text{ seconds}\), correct to the nearest second.
Calculate the lower bound for the average speed of the athlete. Give your answer correct to 3 significant figures.
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PastPaper.workedSolution
To find the lower bound of the speed, we use the formula: \[\text{Speed}_{\text{min}} = \frac{\text{Distance}_{\text{min}}}{\text{Time}_{\text{max}}}\]
First, find the lower bound of the distance: - Distance is \(400\text{ m}\) to the nearest \(10\text{ m}\), so \(\text{Distance}_{\text{min}} = 395\text{ m}\).
Next, find the upper bound of the time: - Time is \(52\text{ s}\) to the nearest second, so \(\text{Time}_{\text{max}} = 52.5\text{ s}\).
Now, calculate the lower bound of the average speed: \[\text{Speed}_{\text{min}} = \frac{395}{52.5} \approx 7.5238... \text{ m/s}\]
Correct to 3 significant figures, this is \(7.52\text{ m/s}\).
PastPaper.markingScheme
M1: For finding either the lower bound of distance (\(395\)) or the upper bound of time (\(52.5\)). M1: For a division using \(\frac{\text{their } 395}{\text{their } 52.5}\), where \(390 \le \text{their } 395 < 400\) and \(52 < \text{their } 52.5 \le 53\). A1: For \(7.52\) (or equivalent accurate to 3 sig figs).
PastPaper.question 24 · Structured Problem Solving
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Evelyn invests \(\pounds 8000\) in a savings account. The account pays \(3\%\) compound interest per annum for the first two years, and then \(1.5\%\) compound interest per annum for the third year.
Calculate the total value of Evelyn's investment at the end of the 3 years. Give your answer to the nearest penny.
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PastPaper.workedSolution
To find the value after the first two years at \(3\%\) compound interest: \[\text{Value after 2 years} = 8000 \times (1.03)^2 = 8000 \times 1.0609 = \pounds 8487.20\]
To find the value after the third year at \(1.5\%\) compound interest: \[\text{Value after 3 years} = 8487.20 \times 1.015 = \pounds 8614.508\]
Rounding to the nearest penny gives \(\pounds 8614.51\).
PastPaper.markingScheme
M1: For a method to calculate the value of the investment after 2 years, e.g. \(8000 \times 1.03^2\) or \(8487.2(0)\). M1: For a complete method to find the final value after applying the 3rd year interest, e.g. \(\text{their } 8487.20 \times 1.015\). A1: For \(8614.51\).
PastPaper.question 25 · Structured Problem Solving
3 PastPaper.marks
Make \(p\) the subject of the formula: \[r = \frac{3p + 2}{5 - p}\]
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PastPaper.workedSolution
Multiply both sides of the equation by \(5 - p\) to eliminate the fraction: \[r(5 - p) = 3p + 2\]
Expand the brackets on the left side: \[5r - rp = 3p + 2\]
Rearrange the equation to collect all terms involving \(p\) on one side and other terms on the opposite side: \[5r - 2 = 3p + rp\]
Factorise \(p\) out of the right side: \[5r - 2 = p(3 + r)\]
Divide both sides by \(3 + r\) to isolate \(p\): \[p = \frac{5r - 2}{3 + r}\]
PastPaper.markingScheme
M1: For a method to clear the fraction, e.g., multiplying both sides by \((5 - p)\) to get \(r(5 - p) = 3p + 2\). M1: For expanding and gathering terms in \(p\) on one side and constant/non-\(p\) terms on the other, e.g. \(5r - 2 = 3p + rp\). A1: For \(p = \frac{5r - 2}{3 + r}\) (or equivalent, such as \(p = \frac{2 - 5r}{-3 - r}\)).
PastPaper.question 26 · Multi-Step Application
5 PastPaper.marks
A solid prism has a cross-section in the shape of a trapezium. The parallel sides of the trapezium have lengths of \(6\text{ cm}\) and \(10\text{ cm}\). The perpendicular distance between the parallel sides is \(5\text{ cm}\). The prism has a length of \(12\text{ cm}\).
The prism is made of metal with a density of \(7.8\text{ g/cm}^3\). The cost of the metal is \(\text{£}4.50\) per kilogram.
Work out the total cost of the metal needed to make \(50\) of these prisms.
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PastPaper.workedSolution
1. Find the area of the trapezium cross-section: \(\text{Area} = \frac{1}{2}(a + b)h = \frac{1}{2}(6 + 10) \times 5 = 8 \times 5 = 40\text{ cm}^2\)
2. Find the volume of one prism: \(\text{Volume} = \text{Area} \times \text{length} = 40 \times 12 = 480\text{ cm}^3\)
3. Find the total volume of 50 prisms: \(\text{Total Volume} = 480 \times 50 = 24,000\text{ cm}^3\)
4. Find the total mass of the metal in grams: \(\text{Mass} = \text{Density} \times \text{Volume} = 7.8 \times 24,000 = 187,200\text{ g}\)
5. Convert the mass to kilograms: \(\text{Mass in kg} = 187,200 \div 1000 = 187.2\text{ kg}\)
6. Calculate the total cost: \(\text{Cost} = 187.2 \times \text{£}4.50 = \text{£}842.40\)
PastPaper.markingScheme
M1: for a correct method to find the area of the cross-section, e.g., \(\frac{1}{2}(6 + 10) \times 5\) (\(= 40\)) M1: for finding the volume of 1 prism (\(480\)) or 50 prisms (\(24,000\)) M1: for a correct method to find the total mass using density, e.g., \(24,000 \times 7.8\) (\(= 187,200\)) M1: for converting grams to kilograms (\(\div 1000\)) and multiplying by \(4.50\) A1: for \(842.40\) (or \(£842.40\), accept \(842.4\) with a loss of the final accuracy mark if not written as currency)
PastPaper.question 27 · Multi-Step Application
5 PastPaper.marks
A rectangular garden has length \((2x + 5)\text{ m}\) and width \((x + 3)\text{ m}\). A square patio of side length \((x - 1)\text{ m}\) is built inside the garden. The remaining area of the garden is grass. The area of the grass is \(62\text{ m}^2\).
Work out the perimeter of the garden.
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PastPaper.workedSolution
1. Express the areas of the garden and the patio algebraically: \(\text{Area of garden} = (2x + 5)(x + 3) = 2x^2 + 11x + 15\) \(\text{Area of patio} = (x - 1)^2 = x^2 - 2x + 1\)
2. Set up the equation for the remaining grass area: \(\text{Grass Area} = \text{Area of garden} - \text{Area of patio}\) \(62 = (2x^2 + 11x + 15) - (x^2 - 2x + 1)\) \(62 = x^2 + 13x + 14\)
3. Rearrange into a standard quadratic equation: \(x^2 + 13x - 48 = 0\)
4. Factorise the quadratic equation: \((x + 16)(x - 3) = 0\) Since dimensions must be positive, \(x\) must be positive, so \(x = 3\) (rejecting \(x = -16\)).
5. Calculate the dimensions of the garden: \(\text{Length} = 2(3) + 5 = 11\text{ m}\) \(\text{Width} = 3 + 3 = 6\text{ m}\)
M1: for expanding \((2x + 5)(x + 3)\) to get \(2x^2 + 11x + 15\) (with at least 3 terms correct) or \((x - 1)^2\) to get \(x^2 - 2x + 1\) (with at least 2 terms correct) M1: for establishing the equation \((2x^2 + 11x + 15) - (x^2 - 2x + 1) = 62\) M1: for simplifying the equation to standard quadratic form, e.g., \(x^2 + 13x - 48 = 0\) M1: for solving the quadratic equation to find \(x = 3\) A1: for \(34\) (or \(34\text{m}\))
PastPaper.question 28 · Multi-Step Application
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There are \(6\) red beads and some green beads in a bag. The total number of beads in the bag is \(n\). Two beads are taken at random from the bag without replacement. The probability that both beads are red is \(\frac{1}{3}\).
Work out the probability that the two beads have different colours.
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1. Express the probability that both beads are red: \(\text{P(Red, Red)} = \frac{6}{n} \times \frac{5}{n-1} = \frac{30}{n(n-1)}\)
2. Solve for \(n\): \(\frac{30}{n(n-1)} = \frac{1}{3} \implies n(n-1) = 90\) \(n^2 - n - 90 = 0\) \((n - 10)(n + 9) = 0\) Since \(n\) must be positive, \(n = 10\).
3. Determine the number of green beads: There are \(10\) beads in total, so \(10 - 6 = 4\) are green.
4. Calculate the probability of selecting two beads of different colours: \(\text{P(Red, Green)} = \frac{6}{10} \times \frac{4}{9} = \frac{24}{90}\) \(\text{P(Green, Red)} = \frac{4}{10} \times \frac{6}{9} = \frac{24}{90}\) \(\text{P(Different Colours)} = \frac{24}{90} + \frac{24}{90} = \frac{48}{90} = \frac{8}{15}\)
PastPaper.markingScheme
M1: for establishing the algebraic product for \(\text{P(Red, Red)}\), e.g., \(\frac{6}{n} \times \frac{5}{n-1}\) M1: for creating the equation \(\frac{30}{n(n-1)} = \frac{1}{3}\) or \(n^2 - n - 90 = 0\) M1: for solving the quadratic equation to find \(n = 10\) M1: for a complete method to find the probability of different colours, e.g., \(2 \times \left(\frac{6}{10} \times \frac{4}{9}\right)\) A1: for \(\frac{8}{15}\) (accept equivalent fractions such as \(\frac{48}{90}\) or decimal \(0.533\) or better)
PastPaper.question 29 · Multi-Step Application
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A ship sails from Port A to Point B on a bearing of \(060^\circ\). The distance from A to B is \(12\text{ km}\). The ship then sails from Point B to Point C on a bearing of \(130^\circ\). The distance from B to C is \(18\text{ km}\).
Work out the bearing of Point C from Port A. Give your answer to the nearest degree.
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1. Determine the interior angle \(ABC\): The line from B back to A is at a direction of \(60^\circ + 180^\circ = 240^\circ\). The bearing of C from B is \(130^\circ\). Therefore, the interior angle \(ABC = 240^\circ - 130^\circ = 110^\circ\).
2. Use the Cosine Rule to find the distance \(AC\): \(AC^2 = AB^2 + BC^2 - 2 \times AB \times BC \times \cos(ABC)\) \(AC^2 = 12^2 + 18^2 - 2 \times 12 \times 18 \times \cos(110^\circ)\) \(AC^2 = 144 + 324 - 432 \times (-0.34202)\) \(AC^2 = 468 + 147.75 = 615.75\) \(AC = \sqrt{615.75} \approx 24.814\text{ km}\)
3. Use the Sine Rule to find the angle \(BAC\): \(\frac{\sin(BAC)}{BC} = \frac{\sin(ABC)}{AC}\) \(\frac{\sin(BAC)}{18} = \frac{\sin(110^\circ)}{24.814}\) \(\sin(BAC) = 18 \times \frac{0.93969}{24.814} \approx 0.6816\) \(\text{Angle } BAC = \sin^{-1}(0.6816) \approx 42.97^\circ\)
4. Calculate the bearing of C from A: \(\text{Bearing} = 60^\circ + \text{Angle } BAC = 60^\circ + 42.97^\circ = 102.97^\circ\) To the nearest degree, this is \(103^\circ\).
PastPaper.markingScheme
M1: for calculating the angle \(ABC = 110^\circ\) (may be shown on a sketch) M1: for applying the Cosine Rule correctly to find \(AC\), e.g., \(12^2 + 18^2 - 2 \times 12 \times 18 \times \cos(110^\circ)\) A1: for finding \(AC \approx 24.8\text{ km}\) (or value in the range \(24.8\) to \(24.82\)) M1: for applying the Sine Rule (or Cosine Rule) correctly to find the angle \(BAC\), leading to \(BAC \approx 43.0^\circ\) A1: for \(103\) (accept \(103^\circ\) or answers in the range \(102.9^\circ\) to \(103.1^\circ\))
PastPaper.question 30 · Multi-Step Application
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On 1st January 2020, Mia made two investments: 1. She bought an industrial machine for \(\text{£}80,000\). The value of the machine depreciated by \(10\%\) in 2020, by \(15\%\) in 2021, and by \(x\%\) in 2022. 2. She deposited \(\text{£}50,000\) in a savings account paying \(4\%\) per annum compound interest.
On 1st January 2023, the value of the machine was \(\text{£}10,343.20\) less than the amount in the savings account.
Work out the value of \(x\).
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PastPaper.workedSolution
1. Calculate the compound interest savings account value after 3 years (on 1st January 2023): \(\text{Savings Value} = 50,000 \times 1.04^3 = 50,000 \times 1.124864 = \text{£}56,243.20\)
2. Determine the machine's value on 1st January 2023: \(\text{Machine Value} = 56,243.20 - 10,343.20 = \text{£}45,900\)
3. Calculate the machine's value after 2 years of depreciation (end of 2021): \(\text{Value after Year 1} = 80,000 \times 0.90 = \text{£}72,000\) \(\text{Value after Year 2} = 72,000 \times 0.85 = \text{£}61,200\)
4. Solve for \(x\) using the third-year depreciation multiplier: \(61,200 \times \left(1 - \frac{x}{100}\right) = 45,900\) \(1 - \frac{x}{100} = \frac{45,900}{61,200} = 0.75\) \(\frac{x}{100} = 0.25 \implies x = 25\)
PastPaper.markingScheme
M1: for a correct method to find the compound interest value, e.g., \(50,000 \times 1.04^3\) (\(= 56,243.20\)) M1: for subtracting \(10,343.20\) from their savings total to find the target machine value (\(45,900\)) M1: for calculating the depreciated value of the machine after 2 years: \(80,000 \times 0.90 \times 0.85\) (\(= 61,200\)) M1: for setting up a correct equation or division for the remaining multiplier: \(\frac{45,900}{61,200}\) (\(= 0.75\)) A1: for \(25\)