An original Thinka practice paper modelled on the structure and difficulty of the Jun 2024 (V2) Cambridge International A Level Mathematics (0580) paper. Not affiliated with or reproduced from Cambridge.
Paper 12 (Core)
Answer all questions. Calculators should be used where appropriate.
To factorise completely, find the highest common factor (HCF) of the two terms.
The HCF of 15 and 20 is 5. The HCF of \(x^2\) and \(x\) is \(x\). The HCF of \(y\) and \(y^2\) is \(y\).
Therefore, the overall HCF is \(5xy\).
Divide each term by the HCF: \(15x^2y \div 5xy = 3x\) \(-20xy^2 \div 5xy = -4y\)
Combine these to get the factorised expression: \(5xy(3x - 4y)\)
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M1 for finding any common factor (e.g., \(5\), \(x\), \(y\), \(5x\), \(5y\), or \(xy\)) outside the bracket, e.g., \(5(3x^2y - 4xy^2)\) or \(xy(15x - 20y)\). A1 for the fully correct factorised expression: \(5xy(3x - 4y)\).
PastPaper.question 2 · Short Answer
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A closed rectangular box has length 8 cm, width 5 cm, and height 3 cm. Calculate the total surface area of this box.
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PastPaper.workedSolution
A closed cuboid has 6 faces in total, consisting of 3 pairs of identical faces.
The area of the bottom and top faces is: \(2 \times (8 \times 5) = 2 \times 40 = 80\text{ cm}^2\)
The area of the front and back faces is: \(2 \times (8 \times 3) = 2 \times 24 = 48\text{ cm}^2\)
The area of the left and right faces is: \(2 \times (5 \times 3) = 2 \times 15 = 30\text{ cm}^2\)
Adding these together: Total Surface Area = \(80 + 48 + 30 = 158\text{ cm}^2\).
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M1 for a correct sum of the areas of at least 3 different faces (e.g. \(8 \times 5 + 8 \times 3 + 5 \times 3\) or \(40 + 24 + 15\)). A1 for 158.
PastPaper.question 3 · Short Answer
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Solve the equation \(4(2x - 3) = 5x + 9\).
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PastPaper.workedSolution
First, expand the bracket on the left side: \(8x - 12 = 5x + 9\)
Next, subtract \(5x\) from both sides to group the \(x\) terms together: \(3x - 12 = 9\)
Then, add 12 to both sides to isolate the term with \(x\): \(3x = 21\)
Finally, divide both sides by 3: \(x = 7\)
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M1 for correct expansion of the bracket to \(8x - 12\) or for a correct step in rearranging terms (e.g., \(8x - 5x = 9 + 12\)). A1 for 7.
PastPaper.question 4 · Short Answer
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Find the \(n\)th term of the sequence: 3, 7, 11, 15, 19, ...
Since the difference is constant, this is an arithmetic sequence with a common difference of 4.
The general formula for the \(n\)th term of an arithmetic sequence is \(dn + c\), where \(d\) is the common difference. Here, \(d = 4\), so the formula is \(4n + c\).
Using the first term where \(n = 1\): \(4(1) + c = 3\) \(4 + c = 3\) \(c = -1\)
Therefore, the \(n\)th term of the sequence is \(4n - 1\).
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M1 for any expression of the form \(4n + k\), where \(k\) is any integer constant, or for identifying the common difference of 4. A1 for \(4n - 1\).
PastPaper.question 5 · Short Answer
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A right-angled triangle has a hypotenuse of length 13 cm and one side of length 5 cm. Calculate the length of the third side.
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PastPaper.workedSolution
Using Pythagoras' theorem, \(a^2 + b^2 = c^2\), where \(c\) is the hypotenuse.
Let the third side be \(b\). \(5^2 + b^2 = 13^2\) \(25 + b^2 = 169\)
Subtract 25 from both sides: \(b^2 = 144\)
Take the square root of both sides: \(b = \sqrt{144} = 12\text{ cm}\).
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M1 for a correct application of Pythagoras' theorem to find the shorter side, e.g., \(\sqrt{13^2 - 5^2}\) or \(13^2 = 5^2 + x^2\). A1 for 12.
PastPaper.question 6 · Short Answer
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Maya changes 450 Euros (€) into Dollars ($). The exchange rate is €1 = $1.16. Calculate the amount Maya receives in Dollars.
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PastPaper.workedSolution
To convert Euros to Dollars, multiply the amount in Euros by the exchange rate: \(450 \times 1.16 = 522\).
Therefore, Maya receives $522.
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M1 for the calculation \(450 \times 1.16\). A1 for 522.
PastPaper.question 7 · Short Answer
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Calculate the area of a circle with a diameter of 12 cm. Give your answer correct to 1 decimal place.
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PastPaper.workedSolution
The formula for the area of a circle is \(A = \pi r^2\), where \(r\) is the radius. First, calculate the radius of the circle: \(r = \frac{12}{2} = 6\text{ cm}\).
Rounding to 1 decimal place gives \(113.1\text{ cm}^2\).
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M1 for \(\pi \times 6^2\) or \(\pi \times (12/2)^2\). A1 for 113.1 (accept answers in the range 113.09 to 113.11).
PastPaper.question 8 · Short Answer
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A fair six-sided die is rolled and a fair coin is tossed. Calculate the probability of getting an even number on the die and a Head on the coin. Give your answer as a fraction in its simplest form.
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PastPaper.workedSolution
The probability of rolling an even number (2, 4, or 6) on a six-sided die is: \(P(\text{even}) = \frac{3}{6} = \frac{1}{2}\).
The probability of tossing a Head on a coin is: \(P(\text{Head}) = \frac{1}{2}\).
Since rolling a die and tossing a coin are independent events, multiply the probabilities: \(P(\text{even and Head}) = \frac{1}{2} \times \frac{1}{2} = \frac{1}{4}\).
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M1 for \(\frac{3}{6} \times \frac{1}{2}\) or for listing all 12 possible outcomes and identifying the 3 successful outcomes (e.g. (2,H), (4,H), (6,H)). A1 for \(1/4\).
M1 for correct expansion of at least one bracket (e.g. \(12a - 18b\) or \(-4a + 20b\))\ A1 for \(8a + 2b\) or \(2(4a + b)\)
PastPaper.question 10 · Short Answer
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An electronic tablet costs £240 in the UK. The same tablet costs $351 in the USA. The exchange rate is £1 = $1.30.\ \ Calculate the difference in cost between the tablet in the UK and in the USA, giving your answer in pounds (£).
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PastPaper.workedSolution
First, convert the cost in the USA from dollars to pounds:\ \(\$351 \div 1.30 = £270\)\ \ Next, find the difference in cost between the USA and the UK:\ \(£270 - £240 = £30\)
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M1 for converting USA cost to pounds: \(351 \div 1.30\) (or converting UK cost to dollars: \(240 \times 1.30 = 312\))\ A1 for 30
PastPaper.question 11 · Short Answer
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A cuboid has a length of \(8\text{ cm}\), a width of \(5\text{ cm}\) and a total surface area of \(236\text{ cm}^2\).\ \ Calculate the height of the cuboid.
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PastPaper.workedSolution
Let the height of the cuboid be \(h\text{ cm}\).\ The formula for the total surface area of a cuboid is:\ \(\text{Total Surface Area} = 2(lw + lh + wh)\)\ \ Substitute the given values into the formula:\ \(2(8 \times 5 + 8 \times h + 5 \times h) = 236\)\ \(2(40 + 13h) = 236\)\ \ Divide both sides by 2:\ \(40 + 13h = 118\)\ \ Subtract 40 from both sides:\ \(13h = 78\)\ \ Divide by 13:\ \(h = 6\)
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M1 for setting up the equation \(2(8 \times 5 + 8h + 5h) = 236\) or \(40 + 13h = 118\)\ A1 for 6
PastPaper.question 12 · Short Answer
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A ladder of length \(6.5\text{ m}\) rests against a vertical wall. The foot of the ladder is \(2.5\text{ m}\) from the base of the wall on horizontal ground.\ \ Calculate the angle that the ladder makes with the horizontal ground.
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PastPaper.workedSolution
Let \(\theta\) be the angle between the ladder and the ground.\ The ladder is the hypotenuse, and the ground distance is the adjacent side to the angle \(\theta\).\ Using the cosine ratio:\ \(\cos(\theta) = \frac{\text{Adjacent}}{\text{Hypotenuse}} = \frac{2.5}{6.5}\)\ \ Find \(\theta\):\ \(\theta = \cos^{-1}\left(\frac{2.5}{6.5}\right) \approx 67.38^\circ\)\ \ Rounding to 1 decimal place gives \(67.4^\circ\).
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M1 for \(\cos(\theta) = \frac{2.5}{6.5}\) or \(\cos^{-1}\left(\frac{2.5}{6.5}\right)\)\ A1 for 67.4 (accept 67.38 or answers in range [67.3, 67.4])
Multiply the first equation by 5 and the second equation by 2 to align the coefficients of \(y\):\ \(15x - 10y = 95\)\ \(4x + 10y = 0\)\ \ Add the two equations:\ \(19x = 95\)\ \(x = 5\)\ \ Substitute \(x = 5\) into the second equation:\ \(2(5) + 5y = 0\)\ \(10 + 5y = 0\)\ \(5y = -10\)\ \(y = -2\)
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M1 for correctly multiplying equations to eliminate one variable or substituting \(x = -2.5y\)\ A1 for both correct values: \(x = 5\) and \(y = -2\)
PastPaper.question 14 · Short Answer
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A curve has the equation \(y = x^2 - 4x - 5\).\ \ Find the coordinates of the two points where the curve crosses the \(x\)-axis.
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PastPaper.workedSolution
The curve crosses the \(x\)-axis when \(y = 0\):\ \(x^2 - 4x - 5 = 0\)\ \ Factorise the quadratic expression:\ \((x - 5)(x + 1) = 0\)\ \ So, \(x = 5\) or \(x = -1\).\ \ The coordinates of the points are \((5, 0)\) and \((-1, 0)\).
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M1 for setting \(x^2 - 4x - 5 = 0\) and attempting to factorise or use quadratic formula\ A1 for \((5, 0)\) and \((-1, 0)\) (or equivalent list of coordinates, in either order)
PastPaper.question 15 · Short Answer
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The first four terms of a sequence are \(5, 11, 17, 23, \dots\).\ \ Find an expression, in terms of \(n\), for the \(n\)th term of this sequence.
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PastPaper.workedSolution
The terms of the sequence increase by a constant difference:\ \(11 - 5 = 6\)\ \(17 - 11 = 6\)\ \(23 - 17 = 6\)\ \ Since the common difference is 6, the formula is of the form \(6n + c\).\ For the first term (\(n = 1\)):\ \(6(1) + c = 5 \implies 6 + c = 5 \implies c = -1\)\ \ Therefore, the \(n\)th term is \(6n - 1\).
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M1 for identifying the common difference is 6 (e.g. finding \(6n\) as part of their expression) or trying to use \(a + (n-1)d\)\ A1 for \(6n - 1\)
PastPaper.question 16 · Short Answer
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A sector of a circle has a radius of \(9\text{ cm}\) and an angle of \(120^\circ\) at the centre.\ \ Calculate the perimeter of this sector. Give your answer in terms of \(\pi\).
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PastPaper.workedSolution
The perimeter of a sector consists of the arc length plus two radii:\ \ \\text{Perimeter} = 2r + \\text{Arc length}\ \ Calculate the arc length:\ \(\text{Arc length} = \frac{\theta}{360} \times 2\pi r = \frac{120}{360} \times 2\pi(9) = \frac{1}{3} \times 18\pi = 6\pi\text{ cm}\)\ \ Add the two radii:\ \(2r = 2 \times 9 = 18\text{ cm}\)\ \ Total perimeter:\ \(18 + 6\pi\text{ cm}\)
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M1 for calculating the arc length: \(\frac{120}{360} \times 2\pi \times 9\) (or \(6\pi\))\ A1 for \(18 + 6\pi\) (or \(6\pi + 18\))
PastPaper.question 17 · Short Answer
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Clara changes $480 into Euros (EUR). The exchange rate is $1 = 0.88 EUR. The bank charges a flat commission fee of $15 before converting the money. Calculate the amount of Euros Clara receives.
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PastPaper.workedSolution
First, subtract the flat commission fee from the initial amount: $480 - $15 = $465. Next, convert this remaining amount to Euros using the exchange rate: \(465 \times 0.88 = 409.2\). Therefore, Clara receives 409.20 EUR.
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M1 for subtracting the commission fee correctly: 480 - 15, or for setting up the multiplication: \(x \times 0.88\). A1 for 409.20 or 409.2.
M1 for a correct expansion of at least one bracket (e.g., \(12x - 8\) or \(-3x - 15\)). A1 for the fully simplified expression \(9x - 23\).
PastPaper.question 19 · Short Answer
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In a right-angled triangle \(ABC\), the hypotenuse \(AC = 14\text{ cm}\) and angle \(BAC = 28^\circ\). Angle \(ABC = 90^\circ\). Calculate the length of the side \(BC\), giving your answer correct to 3 significant figures.
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PastPaper.workedSolution
In right-angled triangle \(ABC\), using the sine ratio: \(\sin(BAC) = \frac{\text{Opposite}}{\text{Hypotenuse}} = \frac{BC}{AC}\). Substituting the given values: \(\sin(28^\circ) = \frac{BC}{14}\). Multiplying both sides by 14: \(BC = 14 \times \sin(28^\circ) \approx 6.5727\text{ cm}\). To 3 significant figures, this is 6.57.
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M1 for \(14 \times \sin(28^\circ)\) or \(\sin(28^\circ) = \frac{BC}{14}\). A1 for 6.57 (accept answers in the range 6.57 to 6.573).
PastPaper.question 20 · Short Answer
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Solve the equation: \(\frac{3x - 4}{2} = 10\).
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PastPaper.workedSolution
Multiply both sides of the equation by 2 to eliminate the fraction: \(3x - 4 = 20\). Add 4 to both sides: \(3x = 24\). Divide both sides by 3 to find \(x\): \(x = 8\).
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M1 for multiplying by 2 to get \(3x - 4 = 20\) (or for another correct first step). A1 for \(x = 8\).
PastPaper.question 21 · Short Answer
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Find an expression, in terms of \(n\), for the \(n\)-th term of the sequence: \(1, 5, 9, 13, 17, \dots\).
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PastPaper.workedSolution
The sequence is arithmetic because the difference between consecutive terms is constant: \(5 - 1 = 4\). The formula for the \(n\)-th term of an arithmetic sequence is \(dn + c\), where \(d\) is the common difference. Here, \(d = 4\), so the term is \(4n + c\). Since the first term is 1, when \(n = 1\), we have \(4(1) + c = 1 \implies c = -3\). Therefore, the \(n\)-th term is \(4n - 3\).
PastPaper.markingScheme
M1 for finding the common difference is 4, or for an expression of the form \(4n + k\) (where \(k\) is any constant). A1 for \(4n - 3\).
PastPaper.question 22 · Short Answer
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A solid cylinder has a radius of \(3\text{ cm}\) and a height of \(8\text{ cm}\). Calculate the volume of the cylinder, leaving your answer in terms of \(\pi\).
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PastPaper.workedSolution
The formula for the volume of a cylinder is \(V = \pi r^2 h\). Substitute \(r = 3\) and \(h = 8\): \(V = \pi \times 3^2 \times 8 = \pi \times 9 \times 8 = 72\pi\text{ cm}^3\).
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M1 for substituting values into the cylinder volume formula correctly: \(\pi \times 3^2 \times 8\). A1 for \(72\pi\).
PastPaper.question 23 · Short Answer
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Divide $240$ in the ratio \(3 : 5 : 4\). Calculate the value of the largest share.
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PastPaper.workedSolution
First, find the total number of parts in the ratio: \(3 + 5 + 4 = 12\). Next, find the value of one part: \(\frac{240}{12} = 20\). The largest share corresponds to the largest number in the ratio, which is 5. Therefore, the largest share is \(5 \times 20 = 100\).
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M1 for dividing 240 by the sum of ratio parts: \(240 / (3+5+4)\). A1 for 100.
PastPaper.question 24 · Short Answer
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Write the decimal number \(0.000307\) in standard form.
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PastPaper.workedSolution
To write \(0.000307\) in standard form, move the decimal point 4 places to the right to obtain a number between 1 and 10, which is \(3.07\). Because the original number is less than 1, the exponent is negative: \(3.07 \times 10^{-4}\).
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B1 for \(3.07\) or for \(10^{-4}\) seen in the final answer. B1 for the fully correct standard form \(3.07 \times 10^{-4}\).
PastPaper.question 25 · Short Answer
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Solve the equation: \(4(2x - 3) = 3x + 13\)
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PastPaper.workedSolution
Expand the bracket on the left-hand side: \(8x - 12 = 3x + 13\). Rearrange the terms to collect those with \(x\) on one side and the constant terms on the other side: \(8x - 3x = 13 + 12\), which simplifies to \(5x = 25\). Divide both sides by \(5\) to find \(x\): \(x = 5\).
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M1 for correct expansion of the bracket: \(8x - 12\) (or equivalent progress, e.g. \(5x = 25\) after an expansion error). A1 for \(5\).
Paper 22 (Extended)
Answer all questions. Write all necessary working clearly.
Next, factorise the denominator using the difference of two squares: \(x^2 - 16 = (x - 4)(x + 4)\).
Now, divide the numerator by the denominator and cancel out the common factor \((x - 4)\): \(\frac{(3x - 2)(x - 4)}{(x - 4)(x + 4)} = \frac{3x - 2}{x + 4}\).
PastPaper.markingScheme
M1 for factorising the numerator correctly: \((3x - 2)(x - 4)\) M1 for factorising the denominator correctly: \((x - 4)(x + 4)\) A1 for the final simplified fraction: \(\frac{3x - 2}{x + 4}\)
PastPaper.question 2 · Medium Answer
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A sector of a circle has a radius of \(7.2\text{ cm}\) and an angle of \(135^\circ\). Calculate the perimeter of this sector. Give your answer correct to 1 decimal place.
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PastPaper.workedSolution
The formula for the arc length of a sector is: \(\text{Arc length} = \frac{\theta}{360} \times 2\pi r\)
Substitute the given values into the formula: \(\text{Arc length} = \frac{135}{360} \times 2 \times \pi \times 7.2\) \(\text{Arc length} = \frac{3}{8} \times 14.4\pi = 5.4\pi \approx 16.965\text{ cm}\)
The perimeter of the sector is the sum of the arc length and two radii: \(\text{Perimeter} = \text{Arc length} + 2r\) \(\text{Perimeter} = 16.965 + 2 \times 7.2 = 16.965 + 14.4 = 31.365\text{ cm}\)
Rounding to 1 decimal place gives \(31.4\text{ cm}\).
PastPaper.markingScheme
M1 for \(\frac{135}{360} \times 2 \times \pi \times 7.2\) (or equivalent arc length calculation) M1 for adding \(2 \times 7.2\) to their arc length A1 for \(31.4\)
PastPaper.question 3 · Medium Answer
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Find the \(n\)th term of the sequence: \(2, 9, 20, 35, 54, \dots\)
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PastPaper.workedSolution
Let's find the first and second differences: First differences: \(7, 11, 15, 19\) Second differences: \(4, 4, 4\)
Since the second differences are constant, the sequence is quadratic and has the general form \(an^2 + bn + c\). The coefficient \(a\) is half of the second difference: \(a = \frac{4}{2} = 2\)
Now subtract \(2n^2\) from each term in the sequence: For \(n=1\): \(2 - 2(1)^2 = 0\) For \(n=2\): \(9 - 2(2)^2 = 1\) For \(n=3\): \(20 - 2(3)^2 = 2\) For \(n=4\): \(35 - 2(4)^2 = 3\)
The remaining sequence is \(0, 1, 2, 3, \dots\), which has the linear formula \(n - 1\).
Combining the quadratic and linear parts, the \(n\)th term is \(2n^2 + n - 1\).
PastPaper.markingScheme
M1 for finding second difference is 4 (or establishing coefficient of \(n^2\) is 2) M1 for subtracting \(2n^2\) from the terms and attempting to find the linear component (e.g. \(n-1\) or solving equations) A1 for \(2n^2 + n - 1\)
Multiply all terms in the inequality by the lowest common multiple of 3 and 4, which is 12, to clear the fractions: \(4(2x - 5) - 3(x + 2) > 12\)
Expand the brackets: \(8x - 20 - 3x - 6 > 12\)
Simplify the left side by grouping like terms: \(5x - 26 > 12\)
Add 26 to both sides: \(5x > 38\)
Divide by 5: \(x > 7.6\) (or \(x > \frac{38}{5}\))
PastPaper.markingScheme
M1 for multiplying by 12 to clear fractions correctly: \(4(2x - 5) - 3(x + 2) > 12\) M1 for simplifying terms to get \(5x > k\) where \(k\) is a constant (e.g., \(5x > 38\)) A1 for \(x > 7.6\) or \(x > \frac{38}{5}\)
PastPaper.question 5 · Medium Answer
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A ladder of length \(6.5\text{ m}\) leans against a vertical wall. The foot of the ladder is on horizontal ground, \(2.5\text{ m}\) away from the base of the wall. Calculate the angle between the ladder and the horizontal ground. Give your answer correct to 1 decimal place.
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PastPaper.workedSolution
Let \(\theta\) be the angle between the ladder and the horizontal ground. The side adjacent to the angle is the distance from the ladder to the wall: \(\text{Adjacent} = 2.5\text{ m}\). The hypotenuse is the length of the ladder: \(\text{Hypotenuse} = 6.5\text{ m}\).
Using the cosine ratio: \(\cos(\theta) = \frac{\text{Adjacent}}{\text{Hypotenuse}}\) \(\cos(\theta) = \frac{2.5}{6.5}\)
Rounding to 1 decimal place, \(\theta = 67.4^\circ\).
PastPaper.markingScheme
M1 for writing the correct trigonometric ratio: \(\cos(\theta) = \frac{2.5}{6.5}\) (or equivalent) M1 for evaluating \(\theta = \cos^{-1}\left(\frac{2.5}{6.5}\right)\) to obtain \(67.38...\) A1 for \(67.4\)
PastPaper.question 6 · Medium Answer
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Elijah invests \(\$4500\) in a savings account that pays compound interest at a rate of \(2.4\%\) per year. Calculate the total interest earned by Elijah at the end of 5 years. Give your answer correct to the nearest cent.
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PastPaper.workedSolution
Calculate the total amount in the account after 5 years using the compound interest formula: \(A = P \left(1 + \frac{r}{100}\right)^t\) \(A = 4500 \times (1 + 0.024)^5 = 4500 \times 1.024^5\) \(A \approx 4500 \times 1.1258999 = 5066.5496\)
Calculate the interest earned by subtracting the principal from the total amount: \(\text{Interest} = A - P = 5066.5496 - 4500 = 566.5496\)
To the nearest cent, the interest earned is \(\$566.55\).
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M1 for compound interest calculation: \(4500 \times 1.024^5\) M1 for subtracting the principal \(4500\) from their calculated total amount A1 for \(566.55\)
PastPaper.question 7 · Medium Answer
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A cone has a circular base of radius \(4.2\text{ cm}\) and a slant height of \(8.5\text{ cm}\). Calculate the volume of the cone. Give your answer correct to 3 significant figures. [The volume, \(V\), of a cone with radius \(r\) and height \(h\) is \(V = \frac{1}{3}\pi r^2 h\).]
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PastPaper.workedSolution
First, find the perpendicular height, \(h\), of the cone using Pythagoras' theorem: \(h^2 + r^2 = l^2\) where \(l\) is the slant height. \(h^2 + 4.2^2 = 8.5^2\) \(h^2 = 8.5^2 - 4.2^2\) \(h^2 = 72.25 - 17.64 = 54.61\) \(h = \sqrt{54.61} \approx 7.38986\text{ cm}\)
Rounding to 3 significant figures gives \(137\text{ cm}^3\).
PastPaper.markingScheme
M1 for \(h = \sqrt{8.5^2 - 4.2^2}\) (or finding \(h \approx 7.39\)) M1 for substituting \(r=4.2\) and their \(h\) into \(\frac{1}{3} \pi r^2 h\) A1 for \(137\) (accept answers in the range \([136.5, 137.0]\))
PastPaper.question 8 · Medium Answer
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A bag contains 5 red balls and 7 blue balls. Two balls are chosen at random from the bag without replacement. Calculate the probability that both balls are of the same colour.
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PastPaper.workedSolution
The total number of balls in the bag is \(5 + 7 = 12\). We want to find the probability of choosing either two red balls or two blue balls.
Calculate the probability of choosing two red balls: \(P(\text{Red, Red}) = \frac{5}{12} \times \frac{4}{11} = \frac{20}{132}\)
Calculate the probability of choosing two blue balls: \(P(\text{Blue, Blue}) = \frac{7}{12} \times \frac{6}{11} = \frac{42}{132}\)
Since these events are mutually exclusive, add the probabilities together: \(P(\text{same colour}) = \frac{20}{132} + \frac{42}{132} = \frac{62}{132}\)
Simplifying the fraction: \(P(\text{same colour}) = \frac{31}{66}\) (or approximately \(0.470\))
PastPaper.markingScheme
M1 for \(\frac{5}{12} \times \frac{4}{11}\) or \(\frac{7}{12} \times \frac{6}{11}\) M1 for \(\left(\frac{5}{12} \times \frac{4}{11}\right) + \left(\frac{7}{12} \times \frac{6}{11}\right)\) A1 for \(\frac{31}{66}\) (or \(0.47\) or \(0.470\))
We can solve the simultaneous equations by equating coefficients.
Multiply the first equation by 2: \(8x - 6y = 35\)
Multiply the second equation by 3: \(9x + 6y = 7.5\)
Add the two resulting equations to eliminate \(y\): \((8x - 6y) + (9x + 6y) = 35 + 7.5\) \(17x = 42.5\) \(x = 2.5\)
Substitute \(x = 2.5\) into the second equation: \(3(2.5) + 2y = 2.5\) \(7.5 + 2y = 2.5\) \(2y = -5\) \(y = -2.5\)
PastPaper.markingScheme
M1 for a valid method to eliminate one variable (e.g., multiplying equations to equate coefficients) A1 for x = 2.5 A1 for y = -2.5 (or equivalent fractions)
PastPaper.question 10 · Medium Answer
2.92 PastPaper.marks
A sector of a circle has a radius of \(12\text{ cm}\) and an arc length of \(15\text{ cm}\). Calculate the area of this sector.
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PastPaper.workedSolution
Let the angle of the sector at the center be \(\theta\) degrees.
The arc length of a sector is given by: \(L = \frac{\theta}{360} \times 2\pi r\)
Substitute the given values into the formula: \(15 = \frac{\theta}{360} \times 2\pi (12)\) \(15 = \frac{\theta}{360} \times 24\pi\) \(\frac{\theta}{360} = \frac{15}{24\pi}\)
The area of the sector is given by: \(A = \frac{\theta}{360} \times \pi r^2\)
M1 for a correct expression linking the sector angle to the arc length, e.g., \(\frac{\theta}{360} \times 2\pi (12) = 15\) or using radians \(\theta = 1.2\) M1 for substituting their angle expression into the area of a sector formula A1 for 90
PastPaper.question 11 · Medium Answer
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A solid metal sphere of radius \(3\text{ cm}\) is melted down and recast into a solid right circular cone of height \(3\text{ cm}\). Calculate the radius of the base of this cone.
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PastPaper.workedSolution
First, calculate the volume of the sphere using \(V = \frac{4}{3}\pi r^3\): \(V_{\text{sphere}} = \frac{4}{3} \times \pi \times 3^3 = 36\pi\text{ cm}^3\)
The volume of a cone is given by \(V = \frac{1}{3}\pi R^2 h\). Since the volume is conserved: \(\frac{1}{3}\pi R^2 (3) = 36\pi\) \(\pi R^2 = 36\pi\) \(R^2 = 36\) \(R = 6\text{ cm}\)
PastPaper.markingScheme
M1 for equating the volume of the sphere and the cone: \(\frac{4}{3}\pi (3)^3 = \frac{1}{3}\pi R^2 (3)\) M1 for simplifying to \(R^2 = 36\) A1 for 6
PastPaper.question 12 · Medium Answer
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The \(n\)-th term of a sequence is given by \(T_n = an^2 + bn - 3\).
The 2nd term is 13 and the 4th term is 53.
Find the value of \(a\) and the value of \(b\).
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PastPaper.workedSolution
Substitute \(n = 2\) and \(n = 4\) into the formula for \(T_n\):
Subtract Equation 1 from Equation 2: \((4a + b) - (2a + b) = 14 - 8\) \(2a = 6 \implies a = 3\)
Substitute \(a = 3\) back into Equation 1: \(2(3) + b = 8 \implies 6 + b = 8 \implies b = 2\)
PastPaper.markingScheme
M1 for creating two correct simultaneous equations in terms of a and b (e.g. \(4a + 2b = 16\) and \(16a + 4b = 56\)) A1 for a = 3 A1 for b = 2
PastPaper.question 13 · Medium Answer
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A bag contains 5 red marbles and 3 blue marbles. Two marbles are drawn at random one after the other without replacement. Calculate the probability that the two marbles drawn are of different colours. Give your answer as a fraction in its simplest form.
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PastPaper.workedSolution
To get different colours, the two possible mutually exclusive outcomes are: 1) Drawing a Red marble first, then a Blue marble. 2) Drawing a Blue marble first, then a Red marble.
Calculate the probability of each outcome: \(P(\text{Red, Blue}) = \frac{5}{8} \times \frac{3}{7} = \frac{15}{56}\) \(P(\text{Blue, Red}) = \frac{3}{8} \times \frac{5}{7} = \frac{15}{56}\)
Sum these probabilities to find the total probability: \(P(\text{Different}) = \frac{15}{56} + \frac{15}{56} = \frac{30}{56} = \frac{15}{28}\)
PastPaper.markingScheme
M1 for calculating one correct product of probabilities (e.g., \(\frac{5}{8} \times \frac{3}{7}\)) M1 for summing the two correct probabilities (\(\frac{15}{56} + \frac{15}{56}\)) A1 for \(\frac{15}{28}\) (or equivalent decimals such as 0.536)
PastPaper.question 14 · Medium Answer
2.92 PastPaper.marks
Solve the inequality: \[-5 < 2x - 3 \le 7\]
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PastPaper.workedSolution
To solve the compound inequality, perform the same operations on all three parts:
First, add 3 to all parts: \(-5 + 3 < 2x \le 7 + 3\) \(-2 < 2x \le 10\)
Next, divide all parts by 2: \(-1 < x \le 5\)
PastPaper.markingScheme
M1 for adding 3 to all parts of the inequality (e.g., to get \(-2 < 2x \le 10\)) A1 for x > -1 A1 for \(x \le 5\) (or A2 for the full statement \(-1 < x \le 5\))
PastPaper.question 15 · Medium Answer
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A rectangular field has a length of \(24\text{ m}\). A path runs diagonally from one corner of the field to the opposite corner. The length of the path is \(25\text{ m}\). Calculate the width of the field.
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PastPaper.workedSolution
Let the width of the field be \(w\text{ m}\).
The rectangular field, length, and diagonal path form a right-angled triangle. By Pythagoras' theorem: \[w^2 + 24^2 = 25^2\] \[w^2 + 576 = 625\] \[w^2 = 625 - 576\] \[w^2 = 49\] \[w = \sqrt{49} = 7\text{ m}\]
PastPaper.markingScheme
M1 for applying Pythagoras' theorem: \(w^2 + 24^2 = 25^2\) M1 for \(w^2 = 625 - 576\) or \(w = \sqrt{49}\) A1 for 7
PastPaper.question 16 · Medium Answer
2.92 PastPaper.marks
In a sale, the price of a laptop is reduced by \(15\%\) to \(\$578\). Calculate the original price of the laptop.
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PastPaper.workedSolution
Let \(P\) be the original price of the laptop.
A reduction of \(15\%\) means the sale price is \(100\% - 15\% = 85\%\) of the original price.
M1 for recognizing that \(\$578\) represents \(85\%\) of the original price, i.e., \(0.85P = 578\) or \(\frac{578}{85} \times 100\) A1 for partial division or calculation step (e.g., \(578 \div 85 = 6.8\)) A1 for 680
Factorise the numerator: \(2x^2 - 5x - 3 = (2x + 1)(x - 3)\). Factorise the denominator: \(4x^2 - 1 = (2x + 1)(2x - 1)\). Divide both by the common factor \((2x + 1)\) to get \(\frac{x - 3}{2x - 1}\).
PastPaper.markingScheme
M1 for factorising the numerator to \((2x + 1)(x - 3)\). M1 for factorising the denominator to \((2x + 1)(2x - 1)\). A1 for the correct simplified fraction.
PastPaper.question 18 · Medium Answer
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A toy is made by joining a solid cone to a solid hemisphere of the same radius \(r = 3\) cm. The total height of the toy is \(11\) cm. Calculate the total volume of the toy, leaving your answer as a multiple of \(\pi\).
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PastPaper.workedSolution
The radius of the hemisphere is \(3\) cm, so its height is also \(3\) cm. The height of the cone is the total height minus the radius of the hemisphere: \(11 - 3 = 8\) cm. The volume of the hemisphere is \(\frac{2}{3} \pi r^3 = \frac{2}{3} \pi (3)^3 = 18\pi\) cm\(^3\). The volume of the cone is \(\frac{1}{3} \pi r^2 h = \frac{1}{3} \pi (3)^2 (8) = 24\pi\) cm\(^3\). The total volume is the sum of these two volumes: \(18\pi + 24\pi = 42\pi\) cm\(^3\).
PastPaper.markingScheme
M1 for finding the height of the cone is \(8\) cm. M1 for setting up the volume of the hemisphere or cone, e.g., \(\frac{2}{3} \pi (3)^3\) or \(\frac{1}{3} \pi (3)^2 (8)\). A1 for \(42\pi\).
PastPaper.question 19 · Medium Answer
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In a right-angled triangle \(ABC\), angle \(B = 90^\circ\), \(AB = 7.2\) cm and \(BC = 9.6\) cm. Point \(D\) lies on the line segment \(BC\) such that \(BD = 4.5\) cm. Calculate the size of angle \(ADC\).
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PastPaper.workedSolution
In the right-angled triangle \(ABD\), we can find angle \(ADB\) using trigonometry: \(\tan(\angle ADB) = \frac{AB}{BD} = \frac{7.2}{4.5} = 1.6\). This gives \(\angle ADB = \arctan(1.6) \approx 58.0^\circ\). Since \(D\) lies on the line segment \(BC\), the angle \(ADC\) and angle \(ADB\) lie on a straight line and sum to \(180^\circ\). Thus, \(\angle ADC = 180^\circ - 58.0^\circ = 122.0^\circ\) (to 1 decimal place).
PastPaper.markingScheme
M1 for \(\tan(\angle ADB) = \frac{7.2}{4.5}\) or \(\angle ADB \approx 58.0^\circ\). M1 for subtracting their angle from \(180^\circ\). A1 for \(122\) or \(122.0\).
PastPaper.question 20 · Medium Answer
2.92 PastPaper.marks
Solve the simultaneous equations: \(y = 2x - 3\) and \(x^2 + y^2 = 41\).
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PastPaper.workedSolution
Substitute the expression for \(y\) into the second equation: \(x^2 + (2x - 3)^2 = 41\). Expand the bracket: \(x^2 + 4x^2 - 12x + 9 = 41\). Simplify to get a quadratic equation: \(5x^2 - 12x - 32 = 0\). Factorising gives \((5x + 8)(x - 4) = 0\), which yields \(x = 4\) or \(x = -1.6\). If \(x = 4\), then \(y = 2(4) - 3 = 5\). If \(x = -1.6\), then \(y = 2(-1.6) - 3 = -6.2\).
PastPaper.markingScheme
M1 for setting up the quadratic equation \(5x^2 - 12x - 32 = 0\). M1 for solving the quadratic equation to find two values of \(x\) (or \(y\)). A1 for both pairs of solutions: \((4, 5)\) and \((-1.6, -6.2)\).
PastPaper.question 21 · Medium Answer
2.92 PastPaper.marks
The curve \(y = x^3 - 12x + 5\) has two stationary points. Find the coordinates of the stationary point that lies in the second quadrant (where \(x < 0\) and \(y > 0\)).
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PastPaper.workedSolution
First, find the derivative of the curve: \(\frac{dy}{dx} = 3x^2 - 12\). Set the derivative to \(0\) to find the stationary points: \(3x^2 - 12 = 0 \implies x^2 = 4 \implies x = 2\) or \(x = -2\). Substitute these values back into the original equation to find the corresponding \(y\)-values: For \(x = -2\): \(y = (-2)^3 - 12(-2) + 5 = -8 + 24 + 5 = 21\). For \(x = 2\): \(y = (2)^3 - 12(2) + 5 = 8 - 24 + 5 = -11\). The stationary point in the second quadrant is \((-2, 21)\).
PastPaper.markingScheme
M1 for differentiating to find \(\frac{dy}{dx} = 3x^2 - 12\). M1 for setting their derivative to 0 and solving for \(x = -2\). A1 for \((-2, 21)\).
PastPaper.question 22 · Medium Answer
2.92 PastPaper.marks
Find the \(n\)-th term of the sequence: \(3, 11, 23, 39, 59, \dots\)
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PastPaper.workedSolution
Find the differences between terms: First differences: \(8, 12, 16, 20\). Second differences: \(4, 4, 4\). Since the second differences are constant, the sequence is quadratic and has the form \(an^2 + bn + c\), where \(a = \frac{4}{2} = 2\). Subtracting \(2n^2\) from each term of the sequence: For \(n=1\): \(3 - 2(1)^2 = 1\). For \(n=2\): \(11 - 2(2)^2 = 3\). For \(n=3\): \(23 - 2(3)^2 = 5\). For \(n=4\): \(39 - 2(4)^2 = 7\). The resulting sequence is \(1, 3, 5, 7, \dots\), which has an \(n\)-th term of \(2n - 1\). Therefore, the overall \(n\)-th term is \(2n^2 + 2n - 1\).
PastPaper.markingScheme
M1 for finding second difference of 4, or \(a = 2\). M1 for finding the linear sequence part \(2n - 1\). A1 for \(2n^2 + 2n - 1\).
PastPaper.question 23 · Medium Answer
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Liam invests \(\$4500\) in a savings account that pays compound interest at a rate of \(3.2\%\) per year. Calculate the number of complete years it will take for the value of Liam's investment to exceed \(\$6000\) for the first time.
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PastPaper.workedSolution
Let \(n\) be the number of years. The investment value is given by \(4500 \times (1.032)^n\). We need this value to exceed \(\$6000\): \(4500 \times (1.032)^n > 6000 \implies 1.032^n > \frac{4}{3} \approx 1.3333\). Testing values of \(n\): For \(n = 9\): \(4500 \times 1.032^9 \approx 5968.04\). For \(n = 10\): \(4500 \times 1.032^{10} \approx 6159.02\). Thus, it will take \(10\) complete years for the investment to exceed \(\$6000\).
PastPaper.markingScheme
M1 for setting up the inequality or equation \(4500 \times 1.032^n > 6000\). M1 for evaluating for \(n=9\) or \(n=10\). A1 for \(10\).
PastPaper.question 24 · Medium Answer
2.92 PastPaper.marks
In triangle \(PQR\), \(PQ = 8\) cm, \(QR = 13\) cm and \(PR = 7\) cm. Find the size of the angle \(QPR\).
Olivia runs a small craft business making and selling handmade ceramic mugs. (a) She buys clay for \$42.00 and glaze for \$18.00. She uses all of these materials to make 15 mugs. Calculate the cost price of making one mug. (b) Olivia sells each mug for \$7.50. Calculate her percentage profit on each mug. (c) Olivia decides to invest \$1400 of her total sales profit in a savings account. The account pays simple interest at a rate of 3.5% per year. Calculate the total value of her investment after 4 years.
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PastPaper.workedSolution
(a) Total cost = \$42.00 + \$18.00 = \$60.00. Cost price per mug = \$60.00 \\div 15 = \$4.00. (b) Profit per mug = Selling price - Cost price = \$7.50 - \$4.00 = \$3.50. Percentage profit = (\$3.50 / \$4.00) * 100 = 87.5%. (c) Simple Interest = P * R * T / 100 = 1400 * 3.5 * 4 / 100 = 196. Total value = 1400 + 196 = \$1596.
PastPaper.markingScheme
(a) [3 marks total]: M1 for adding 42.00 + 18.00 (= 60.00), M1 for dividing their total by 15, A1 for 4.00. (b) [4 marks total]: M1 for finding profit per mug: 7.50 - 4.00 (= 3.50), M1 for dividing profit by cost price (3.50 / 4.00), M1 for multiplying by 100, A1 for 87.5. (c) [4.56 marks total]: M1 for interest formula setup: 1400 * 3.5 * 4 / 100, A1 for finding interest = 196, M1 for adding interest to 1400, A1.56 for 1596.
PastPaper.question 2 · Structured
11.56 PastPaper.marks
A closed metal cylinder has a radius of 6 cm and a height of 15 cm. (a) Calculate the volume of the cylinder. Give your answer in terms of \\pi. (b) Calculate the total surface area of the cylinder. Give your answer correct to 1 decimal place. (c) The cylinder is melted down and recast into 5 solid spheres of equal size. Calculate the radius of each sphere. Give your answer correct to 2 decimal places. [The volume, \(V\), of a sphere with radius \(r\) is \(V = \frac{4}{3}\pi r^3\).]
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PastPaper.workedSolution
(a) Volume of cylinder = \\pi * r^2 * h = \\pi * 6^2 * 15 = 540\\pi cm^3. (b) Total surface area = 2\\pi r^2 + 2\\pi r h = 2\\pi(6)^2 + 2\\pi(6)(15) = 72\\pi + 180\\pi = 252\\pi \\approx 791.68 cm^2. Correct to 1 d.p. is 791.7 cm^2. (c) Volume of one sphere = 540\\pi / 5 = 108\\pi cm^3. Using volume of sphere formula: (4/3)\\pi r^3 = 108\\pi \\implies (4/3)r^3 = 108 \\implies r^3 = 81 \\implies r = \\sqrt[3]{81} \\approx 4.3267 cm. Correct to 2 d.p. is 4.33 cm.
PastPaper.markingScheme
(a) [3 marks total]: M1 for cylinder volume formula, M1 for substituting 6 and 15, A1 for 540\\pi. (b) [4 marks total]: M1 for surface area formula, M1 for substituting values, A1 for 252\\pi or 791.68..., A1 for 791.7. (c) [4.56 marks total]: M1 for dividing volume by 5: 108\\pi, M1 for setting up equation: (4/3)\\pi r^3 = 108\\pi, M1 for finding r^3 = 81, A1.56 for 4.33.
PastPaper.question 3 · Structured
11.56 PastPaper.marks
A ladder of length 4.5 m is leaning against a vertical wall. (a) The foot of the ladder is 1.8 m away from the base of the wall. Calculate the height up the wall that the ladder reaches. Give your answer correct to 3 significant figures. (b) Calculate the angle that the ladder makes with the horizontal ground. Give your answer correct to 1 decimal place. (c) The ladder is adjusted so that it now reaches a height of 4.2 m up the wall. Calculate the new distance from the foot of the ladder to the base of the wall. Give your answer correct to 3 significant figures.
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PastPaper.workedSolution
(a) Using Pythagoras' theorem: h^2 + 1.8^2 = 4.5^2 \\implies h^2 = 20.25 - 3.24 = 17.01 \\implies h = \\sqrt{17.01} \\approx 4.1243 m. To 3 s.f., height is 4.12 m. (b) cos(\\theta) = 1.8 / 4.5 = 0.4 \\implies \\theta = cos^{-1}(0.4) \\approx 66.4218 degrees. To 1 d.p., \\theta = 66.4 degrees. (c) d^2 + 4.2^2 = 4.5^2 \\implies d^2 = 20.25 - 17.64 = 2.61 \\implies d = \\sqrt{2.61} \\approx 1.6155 m. To 3 s.f., distance is 1.62 m.
PastPaper.markingScheme
(a) [3.56 marks total]: M1 for Pythagoras setup 4.5^2 - 1.8^2, A1 for 17.01, M1 for square-rooting, A0.56 for 4.12. (b) [4 marks total]: M1 for cos ratio, M1 for cos(\\theta) = 1.8/4.5, M1 for cos^{-1}(0.4), A1 for 66.4. (c) [4 marks total]: M1 for Pythagoras setup d^2 = 4.5^2 - 4.2^2, M1 for d^2 = 2.61, M1 for \\sqrt{2.61}, A1 for 1.62.
(a) [3 marks total]: M1 for 6x - 15, M1 for -4x + 8, A1 for 2x - 7. (b) [3.56 marks total]: M1 for finding any common factor like 2, 3, x or y, M1.56 for full common factor 6xy, A1 for 6xy(3x - 2y). (c) [5 marks total]: M1 for (x-3)(x+3), M1 for 5(x+3), M2 for cancelling (x+3), A1 for (x-3)/5.
PastPaper.question 5 · Structured
11.56 PastPaper.marks
(a) Solve the simultaneous equations: 4x + 3y = 25, 3x - 2y = 6. (b) Solve the equation: \(\frac{5x - 2}{3} = x + 4\).
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PastPaper.workedSolution
(a) Multiply first equation by 2 and second by 3: 8x + 6y = 50, 9x - 6y = 18. Add equations: 17x = 68 \\implies x = 4. Substitute x = 4 into second equation: 3(4) - 2y = 6 \\implies 12 - 2y = 6 \\implies 2y = 6 \\implies y = 3. (b) Multiply both sides by 3: 5x - 2 = 3(x + 4) \\implies 5x - 2 = 3x + 12 \\implies 2x = 14 \\implies x = 7.
PastPaper.markingScheme
(a) [5.56 marks total]: M1 for attempt to eliminate variable, M1 for 17x = 68, A1 for x = 4, M1 for substituting x back, A1.56 for y = 3. (b) [6 marks total]: M2 for 5x - 2 = 3(x + 4), M1 for 3x + 12, M2 for isolating terms to 2x = 14, A1 for x = 7.
PastPaper.question 6 · Structured
11.56 PastPaper.marks
Consider the function \(y = x^2 - 3x - 4\). (a) The table shows some values for this function. [x: -2, -1, 0, 1, 2, 3, 4, 5] [y: 6, p, -4, q, -6, r, 0, 6]. Find the values of p, q, and r. (b) Write down the equation of the line of symmetry of the graph of \(y = x^2 - 3x - 4\). (c) Solve the equation \(x^2 - 3x - 4 = 0\) algebraically to find the x-coordinates of the points where the graph intersects the x-axis.
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PastPaper.workedSolution
(a) If x = -1, y = (-1)^2 - 3(-1) - 4 = 0, so p = 0. If x = 1, y = 1^2 - 3(1) - 4 = -6, so q = -6. If x = 3, y = 3^2 - 3(3) - 4 = -4, so r = -4. (b) The line of symmetry is halfway between x = 1 and x = 2 (where y = -6), which is x = 1.5. (c) Factorise: (x - 4)(x + 1) = 0 \\implies x = 4 or x = -1.
PastPaper.markingScheme
(a) [3 marks total]: B1 for p = 0, B1 for q = -6, B1 for r = -4. (b) [4 marks total]: M2 for identifying midpoint or using formula -b/2a, A2 for x = 1.5. (c) [4.56 marks total]: M2 for factorising to (x-4)(x+1), A1 for x = 4, A1.56 for x = -1.
PastPaper.question 7 · Structured
11.56 PastPaper.marks
Here are the first four terms of an arithmetic sequence: 7, 13, 19, 25, ... (a) Write down the next term of this sequence. (b) Find an expression for the n-th term of this sequence. (c) Find the value of the 50th term. (d) Show that 425 is not a term in this sequence.
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PastPaper.workedSolution
(a) Common difference is 6. Next term is 25 + 6 = 31. (b) First term is 7, common difference is 6. n-th term = 6n + (7 - 6) = 6n + 1. (c) 50th term = 6(50) + 1 = 301. (d) Set 6n + 1 = 425 \\implies 6n = 424 \\implies n = 70.67. Since n is not a whole number, 425 is not in the sequence.
PastPaper.markingScheme
(a) [2 marks total]: B2 for 31. (b) [4 marks total]: M2 for finding common difference 6, A2 for 6n + 1. (c) [2 marks total]: M1 for substituting 50, A1 for 301. (d) [3.56 marks total]: M1 for 6n + 1 = 425, A1 for n = 70.67, A1.56 for explanation that n must be an integer.
PastPaper.question 8 · Structured
11.56 PastPaper.marks
In triangle ABC, side AB = 8.5 cm, side BC = 12.4 cm, and angle ABC = 58 degrees. (a) Calculate the area of triangle ABC. Give your answer correct to 3 significant figures. (b) Calculate the length of the side AC. Give your answer correct to 3 significant figures. (c) Calculate the perpendicular height of the triangle from the vertex A to the base BC. Give your answer correct to 3 significant figures.
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PastPaper.workedSolution
(a) Area = 0.5 * AB * BC * sin(ABC) = 0.5 * 8.5 * 12.4 * sin(58) \\approx 44.692 cm^2. To 3 s.f., Area is 44.7 cm^2. (b) Cosine Rule: AC^2 = AB^2 + BC^2 - 2 * AB * BC * cos(ABC) = 8.5^2 + 12.4^2 - 2 * 8.5 * 12.4 * cos(58) = 72.25 + 153.76 - 210.8 * 0.5299 = 226.01 - 111.71 = 114.30 cm^2. AC = \\sqrt{114.30} \\approx 10.69 cm. To 3 s.f., AC is 10.7 cm. (c) sin(58) = height / 8.5 \\implies height = 8.5 * sin(58) \\approx 7.208 cm. To 3 s.f., height is 7.21 cm.
PastPaper.markingScheme
(a) [4 marks total]: M1 for area formula, M2 for correct substitution, A1 for 44.7. (b) [4.56 marks total]: M1 for Cosine Rule formula, M1 for 114.3, M1 for square root, A1.56 for 10.7. (c) [3 marks total]: M1 for trig formula or area-height formula, M1 for solving, A1 for 7.21.
PastPaper.question 9 · Structured
11.56 PastPaper.marks
The shape of a garden consists of a rectangle of length \(15\text{ m}\) and width \(8\text{ m}\), and a semicircle with a diameter of \(8\text{ m}\) attached to one of the \(8\text{ m}\) sides of the rectangle.
(a) Calculate the perimeter of the garden. Give your answer correct to 1 decimal place.
(b) Calculate the total area of the garden. Give your answer correct to 1 decimal place.
(c) (i) Grass seed is sold in bags. Each bag of grass seed covers an area of \(18\text{ m}^2\). Calculate the minimum number of bags of grass seed needed to cover the garden.
(ii) Each bag of grass seed costs \(\$12.50\). Calculate the total cost of these bags.
(d) A decorative border is placed around the entire perimeter of the garden. The border costs \(\$8.20\) per metre. Calculate the total cost of this border.
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PastPaper.workedSolution
(a) The perimeter consists of two lengths of the rectangle (\(15\text{ m}\) each), one width of the rectangle (\(8\text{ m}\)), and the curved arc of the semicircle. Curved arc of semicircle = \(\frac{1}{2} \times \pi \times d = \frac{1}{2} \times \pi \times 8 = 4\pi \approx 12.57\text{ m}\). Perimeter = \(15 + 15 + 8 + 4\pi = 38 + 12.57 = 50.57\text{ m}\). Rounding to 1 decimal place gives \(50.6\text{ m}\).
(b) The total area consists of the area of the rectangle and the area of the semicircle. Area of rectangle = \(15 \times 8 = 120\text{ m}^2\). Area of semicircle = \(\frac{1}{2} \times \pi \times r^2 = \frac{1}{2} \times \pi \times 4^2 = 8\pi \approx 25.13\text{ m}^2\). Total Area = \(120 + 25.13 = 145.13\text{ m}^2\). Rounding to 1 decimal place gives \(145.1\text{ m}^2\).
(c) (i) Number of bags required = \(\frac{\text{Total Area}}{18} = \frac{145.13}{18} \approx 8.06\). Since seed must be bought in whole bags, we round up to the next integer: \(9\) bags.
(ii) Total cost = \(9 \times 12.50 = 112.50\).
(d) Total cost of border = \(\text{Perimeter} \times 8.20\). Using the more precise perimeter of \(50.57\text{ m}\): \(50.56637... \times 8.20 = 414.64\). Using the rounded perimeter of \(50.6\text{ m}\): \(50.6 \times 8.20 = 414.92\).
PastPaper.markingScheme
(a) [3 Marks] - M1 for \(15 + 15 + 8\) (or \(38\)) - M1 for \(\frac{1}{2} \times \pi \times 8\) (or \(4\pi\) or \(12.57\)) - A1 for \(50.6\)
(b) [3 Marks] - M1 for \(15 \times 8\) (or \(120\)) - M1 for \(\frac{1}{2} \times \pi \times 4^2\) (or \(8\pi\) or \(25.1\)) - A1 for \(145.1\)
(c)(i) [2 Marks] - M1 for \(\text{their (b)} \div 18\) - A1 for \(9\) (must be an integer greater than their division result)
(c)(ii) [1 Mark] - B1 for \(112.50\) (or FT \(\text{their (c)(i)} \times 12.50\))
(d) [2 Marks] - M1 for \(\text{their (a)} \times 8.20\) - A1 for \(414.64\) or \(414.92\) (or FT \(\text{their (a)} \times 8.20\))
PastPaper.question 10 · Structured
11.56 PastPaper.marks
The shape of a garden consists of a rectangle of length \(15\text{ m}\) and width \(8\text{ m}\), and a semicircle with a diameter of \(8\text{ m}\) attached to one of the \(8\text{ m}\) sides of the rectangle.
(a) Calculate the perimeter of the garden. Give your answer correct to 1 decimal place.
(b) Calculate the total area of the garden. Give your answer correct to 1 decimal place.
(c) (i) Grass seed is sold in bags. Each bag of grass seed covers an area of \(18\text{ m}^2\). Calculate the minimum number of bags of grass seed needed to cover the garden.
(ii) Each bag of grass seed costs \(\$12.50\). Calculate the total cost of these bags.
(d) A decorative border is placed around the entire perimeter of the garden. The border costs \(\$8.20\) per metre. Calculate the total cost of this border.
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PastPaper.workedSolution
(a) The perimeter consists of two lengths of the rectangle (\(15\text{ m}\) each), one width of the rectangle (\(8\text{ m}\)), and the curved arc of the semicircle. Curved arc of semicircle = \(\frac{1}{2} \times \pi \times d = \frac{1}{2} \times \pi \times 8 = 4\pi \approx 12.57\text{ m}\). Perimeter = \(15 + 15 + 8 + 4\pi = 38 + 12.57 = 50.57\text{ m}\). Rounding to 1 decimal place gives \(50.6\text{ m}\).
(b) The total area consists of the area of the rectangle and the area of the semicircle. Area of rectangle = \(15 \times 8 = 120\text{ m}^2\). Area of semicircle = \(\frac{1}{2} \times \pi \times r^2 = \frac{1}{2} \times \pi \times 4^2 = 8\pi \approx 25.13\text{ m}^2\). Total Area = \(120 + 25.13 = 145.13\text{ m}^2\). Rounding to 1 decimal place gives \(145.1\text{ m}^2\).
(c) (i) Number of bags required = \(\frac{\text{Total Area}}{18} = \frac{145.13}{18} \approx 8.06\). Since seed must be bought in whole bags, we round up to the next integer: \(9\) bags.
(ii) Total cost = \(9 \times 12.50 = 112.50\).
(d) Total cost of border = \(\text{Perimeter} \times 8.20\). Using the more precise perimeter of \(50.57\text{ m}\): \(50.56637... \times 8.20 = 414.64\). Using the rounded perimeter of \(50.6\text{ m}\): \(50.6 \times 8.20 = 414.92\).
PastPaper.markingScheme
(a) [3 Marks] - M1 for \(15 + 15 + 8\) (or \(38\)) - M1 for \(\frac{1}{2} \times \pi \times 8\) (or \(4\pi\) or \(12.57\)) - A1 for \(50.6\)
(b) [3 Marks] - M1 for \(15 \times 8\) (or \(120\)) - M1 for \(\frac{1}{2} \times \pi \times 4^2\) (or \(8\pi\) or \(25.1\)) - A1 for \(145.1\)
(c)(i) [2 Marks] - M1 for \(\text{their (b)} \div 18\) - A1 for \(9\) (must be an integer greater than their division result)
(c)(ii) [1 Mark] - B1 for \(112.50\) (or FT \(\text{their (c)(i)} \times 12.50\))
(d) [2 Marks] - M1 for \(\text{their (a)} \times 8.20\) - A1 for \(414.64\) or \(414.92\) (or FT \(\text{their (a)} \times 8.20\))
A drone flies a distance of 120 km from base A to base B at an average speed of \(v\) km/h. (a) Write down an expression, in terms of \(v\), for the time taken in hours. (b) On the return journey, the drone encounters a headwind and its average speed is reduced by 15 km/h. Write down an expression, in terms of \(v\), for the time taken, in hours, for the return journey. (c) The total time for the two journeys is 5.4 hours. (i) Show that \(9v^2 - 535v + 3000 = 0\). (ii) Solve the equation \(9v^2 - 535v + 3000 = 0\), showing all your working. Find the two possible values of \(v\), giving your answers correct to 2 decimal places.
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PastPaper.workedSolution
(a) Time = Distance / Speed = \(120/v\) hours. (b) Return speed = \(v - 15\) km/h. Time taken = \(120/(v-15)\) hours. (c)(i) Total time = \(120/v + 120/(v-15) = 5.4\). Multiplying both sides by 10 and dividing by 6 simplifies this to: \(20/v + 20/(v-15) = 0.9\) which becomes \(200(v-15) + 200v = 9v(v-15)\). This expands to \(400v - 3000 = 9v^2 - 135v\), which rearranges to \(9v^2 - 535v + 3000 = 0\). (c)(ii) Using the quadratic formula: \(v = \frac{535 \pm \sqrt{(-535)^2 - 4(9)(3000)}}{2(9)} = \frac{535 \pm \sqrt{178225}}{18}\). Thus, \(v \approx 53.18\) or \(v \approx 6.27\).
PastPaper.markingScheme
(a) B1 for 120/v. (b) B1 for 120/(v-15). (c)(i) M1 for setting up the equation 120/v + 120/(v-15) = 5.4. M1 for clearing fractions to get 120(v-15) + 120v = 5.4v(v-15). A1 for showing step-by-step algebraic simplification to the final form. (c)(ii) M1 for correct substitution into the quadratic formula. A1 for 53.18. A1 for 6.27.
PastPaper.question 2 · Structured
11.82 PastPaper.marks
A solid metal cylinder has radius \(r\) cm and height \(2r\) cm. A solid metal sphere has radius \(R\) cm. (a) Show that the total surface area of the cylinder is \(6\pi r^2\). (b) The sphere has the same volume as the cylinder. Show that \(R = \sqrt[3]{\frac{3}{2}} r\). (c) Find the ratio of the total surface area of the cylinder to the total surface area of the sphere. Give your answer in the form \(1 : k\), where \(k\) is correct to 3 significant figures.
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PastPaper.workedSolution
(a) Total surface area of a cylinder is \(2\pi r^2 + 2\pi r h\). Since \(h = 2r\), Area = \(2\pi r^2 + 2\pi r(2r) = 2\pi r^2 + 4\pi r^2 = 6\pi r^2\). (b) Volume of cylinder = \(\pi r^2 h = \pi r^2 (2r) = 2\pi r^3\). Volume of sphere = \(\frac{4}{3}\pi R^3\). Since volumes are equal, \(\frac{4}{3}\pi R^3 = 2\pi r^3 \implies 4R^3 = 6r^3 \implies R^3 = \frac{3}{2}r^3 \implies R = \sqrt[3]{\frac{3}{2}} r\). (c) Total surface area of the sphere is \(4\pi R^2 = 4\pi \left(\sqrt[3]{\frac{3}{2}}r\right)^2 = 4\pi (1.5)^{2/3} r^2\). The ratio of cylinder area to sphere area is \(6\pi r^2 : 4\pi (1.5)^{2/3} r^2 = 6 : 4(1.5)^{2/3} \approx 6 : 5.2415 = 1 : 0.87358...\) which rounds to \(1 : 0.874\).
PastPaper.markingScheme
(a) M1 for 2*pi*r^2 + 2*pi*r*(2r). A1 for establishing 6*pi*r^2. (b) M1 for volume of cylinder 2*pi*r^3. M1 for setting 4/3*pi*R^3 = 2*pi*r^3. A1 for simplifying to R^3 = 1.5r^3 and concluding. (c) M1 for expression of sphere surface area 4*pi*R^2. M1 for substituting R in terms of r. M1 for ratio 6 : 4(1.5)^(2/3). A1 for 1 : 0.874.
PastPaper.question 3 · Structured
11.82 PastPaper.marks
(a) Simplify completely: \(\frac{2x^2 - 8}{x^2 + 5x + 6}\). (b) Write as a single fraction in its simplest form: \(\frac{3}{2x-1} - \frac{2}{x+3}\). (c) Factorise completely: \(12ax - 8ay - 3bx + 2by\).
(a) M1 for 2(x-2)(x+2). M1 for (x+2)(x+3). A1 for correct simplified fraction. (b) M1 for 3(x+3) - 2(2x-1). M1 for common denominator (2x-1)(x+3). A1 for (11-x)/((2x-1)(x+3)). (c) M1 for 4a(3x-2y) or -b(3x-2y). A1 for final factorisation.
PastPaper.question 4 · Structured
11.82 PastPaper.marks
A triangular field \(ABC\) has \(AB = 110\) m, \(BC = 85\) m, and angle \(ABC = 72^\circ\). (a) Calculate the length of \(AC\), giving your answer to the nearest meter. (b) Calculate the area of the field, correct to 3 significant figures. (c) A flagpole stands vertically at \(B\). The angle of elevation of the top of the flagpole from \(A\) is \(14^\circ\). Calculate the height of the flagpole, correct to 1 decimal place. (d) Calculate the shortest distance from \(B\) to the side \(AC\), correct to 1 decimal place.
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PastPaper.workedSolution
(a) By the Cosine Rule: \(AC^2 = 110^2 + 85^2 - 2(110)(85)\cos(72^\circ) = 12100 + 7225 - 18700(0.309017) = 13546.38\). Thus, \(AC = \sqrt{13546.38} \approx 116.39\) m, which is \(116\) m to the nearest meter. (b) Area = \(\frac{1}{2} \times AB \times BC \times \sin(ABC) = \frac{1}{2}(110)(85)\sin(72^\circ) \approx 4446.19\) m\(^2\), which is \(4450\) m\(^2\) (or \(4446\) m\(^2\)). (c) In right-angled triangle \(ABF\), \(\tan(14^\circ) = \frac{\text{height}}{110} \implies \text{height} = 110\tan(14^\circ) \approx 27.4\) m. (d) The shortest distance \(d\) is the perpendicular height. Area = \(\frac{1}{2} \times AC \times d \implies 4446.19 = \frac{1}{2}(116.388)d \implies d = \frac{2 \times 4446.19}{116.388} \approx 76.4\) m.
PastPaper.markingScheme
(a) M1 for Cosine Rule formula with correct values. A1 for 116.39. A1 for 116. (b) M1 for Area formula with correct values. A1 for 4450 or 4446. (c) M1 for tan(14) = h/110. A1 for 27.4. (d) M1 for Area = 0.5 * AC * d. A1 for 76.4.
PastPaper.question 5 · Structured
11.82 PastPaper.marks
Consider the function \(f(x) = \frac{12}{x} + x^2 - 6\) for \(x \neq 0\). (a) Complete the table of values: when \(x = -3\), \(y = -1\); when \(x = -2\), \(y = a\); when \(x = -1\), \(y = -17\); when \(x = 0.5\), \(y = 18.25\); when \(x = 1\), \(y = b\); when \(x = 2\), \(y = 4\); when \(x = 3\), \(y = c\). Find the values of \(a\), \(b\), and \(c\). (b) Show that the equation \(\frac{12}{x} + x^2 - 6 = 2x\) can be written as \(x^3 - 2x^2 - 6x + 12 = 0\). (c) (i) Write down the equation of the straight line whose intersection with the graph of \(y = f(x)\) gives the solutions to the equation in part (b). (ii) Given that one intersection point is at \(x = 2\), find the other two exact solutions of \(x^3 - 2x^2 - 6x + 12 = 0\).
(a) B1 for a = -8. B1 for b = 7. B1 for c = 7. (b) M1 for multiplying by x. A1 for correct rearrangement. (c)(i) B1 for y = 2x. (c)(ii) M1 for grouping or polynomial division. A1 for (x^2 - 6)(x-2). A1 for sqrt(6) and -sqrt(6) (or +/-2.45).
PastPaper.question 6 · Structured
11.82 PastPaper.marks
A bag contains 5 red marbles, 4 blue marbles, and 3 green marbles. Two marbles are drawn at random without replacement. (a) Find the probability that both marbles are of the same color. (b) Find the probability that at least one of the marbles is green.
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PastPaper.workedSolution
(a) The total number of marbles is 12. The probability of drawing two marbles of the same color is \(P(RR) + P(BB) + P(GG)\). \(P(RR) = \frac{5}{12} \times \frac{4}{11} = \frac{20}{132}\). \(P(BB) = \frac{4}{12} \times \frac{3}{11} = \frac{12}{132}\). \(P(GG) = \frac{3}{12} \times \frac{2}{11} = \frac{6}{132}\). Total probability = \(\frac{20+12+6}{132} = \frac{38}{132} = \frac{19}{66}\) (or approximately 0.288). (b) The probability that at least one marble is green is \(1 - P(\text{no green})\). \(P(\text{no green}) = P(\text{Red or Blue for both}) = \frac{9}{12} \times \frac{8}{11} = \frac{72}{132} = \frac{6}{11}\). Thus, \(1 - \frac{6}{11} = \frac{5}{11}\) (or approximately 0.455).
PastPaper.markingScheme
(a) M1 for listing P(RR), P(BB), P(GG) with without-replacement denominators. M1 for correct individual products. A1 for 19/66 (or 38/132 or 0.288). (b) M1 for 1 - P(no green) or alternative addition of outcomes. M1 for P(no green) = (9/12)*(8/11). A1 for 5/11 (or 0.455).
PastPaper.question 7 · Structured
11.82 PastPaper.marks
The first four terms of Sequence A, Sequence B, and Sequence C are given. Sequence A: 5, 8, 11, 14, ... Sequence B: 2, 5, 10, 17, ... Sequence C: \(\frac{5}{2}\), \(\frac{8}{5}\), \(\frac{11}{10}\), \(\frac{14}{17}\), ... (a) Find the \(n\)-th term expression for: (i) Sequence A. (ii) Sequence B. (iii) Sequence C. (b) Find the 50th term of Sequence C, giving your answer as a fraction. (c) Sequence D is a geometric sequence: 3, 6, 12, 24, ... (i) Find the \(n\)-th term of Sequence D. (ii) Find the value of \(n\) for which the \(n\)-th term of Sequence D is equal to 12288.
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PastPaper.workedSolution
(a)(i) Sequence A is an arithmetic sequence with a common difference of 3 and first term 5. The \(n\)-th term is \(3n + 2\). (a)(ii) Sequence B has terms that are 1 more than perfect squares: \(1^2+1, 2^2+1, 3^2+1, 4^2+1\). The \(n\)-th term is \(n^2 + 1\). (a)(iii) Sequence C is formed by dividing Sequence A by Sequence B. The \(n\)-th term is \(\frac{3n + 2}{n^2 + 1}\). (b) For \(n = 50\), the term is \(\frac{3(50) + 2}{50^2 + 1} = \frac{152}{2501}\). (c)(i) Sequence D is a geometric sequence with first term \(a = 3\) and common ratio \(r = 2\). The \(n\)-th term is \(3 \times 2^{n-1}\). (c)(ii) Setting \(3 \times 2^{n-1} = 12288 \implies 2^{n-1} = 4096\). Since \(2^{12} = 4096\), we have \(n - 1 = 12 \implies n = 13\).
PastPaper.markingScheme
(a)(i) B1 for 3n + k, B1 for 3n + 2. (a)(ii) M1 for recognising square numbers, A1 for n^2 + 1. (a)(iii) B1 for (3n+2)/(n^2+1). (b) B1 for 152/2501. (c)(i) B1 for 3 * 2^(n-1). (c)(ii) M1 for 3 * 2^(n-1) = 12288, A1 for n = 13.
PastPaper.question 8 · Structured
11.82 PastPaper.marks
Clara, David, and Elena invest money in different accounts. (a) Clara invests \(\$4500\) at a rate of 3.2% per year simple interest. Calculate the total interest Clara has earned at the end of 6 years. (b) David invests \(\$4000\) at a rate of \(r\%\) per year compound interest. At the end of 6 years, the value of David's investment is \(\$4850\). Calculate the value of \(r\), correct to 2 decimal places. (c) On the same day, Elena invests \(\$5000\) in an account that pays compound interest. The interest rate is 2.5% per year for the first 3 years, and then increases to 3.5% per year for the next 3 years. Calculate the total amount in Elena's account at the end of these 6 years, correct to the nearest cent.
(a) M1 for 4500 * 0.032 * 6. A1 for 864. (b) M1 for 4000 * (1 + r/100)^6 = 4850. M1 for (1.2125)^(1/6). A1 for 3.26. (c) M1 for 5000 * (1.025)^3. M1 for multiplying by (1.035)^3. A1 for 5969.84.
PastPaper.question 9 · Structured
11.82 PastPaper.marks
A triangular field \(ABC\) has sides \(AB = 120\text{ m}\), \(BC = 85\text{ m}\) and angle \(ABC = 78^\circ\).
(a) Calculate the length of the boundary \(AC\). [4]
(b) Calculate angle \(ACB\). [3]
(c) Calculate the area of the field. [3]
(d) A straight path is built from \(B\) to the nearest point on the boundary \(AC\). Calculate the length of this path. [2]
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PastPaper.workedSolution
(a) Using the Cosine Rule: \(AC^2 = AB^2 + BC^2 - 2 \times AB \times BC \times \cos(ABC)\) \(AC^2 = 120^2 + 85^2 - 2 \times 120 \times 85 \times \cos(78^\circ)\) \(AC^2 = 14400 + 7225 - 20400 \times 0.20791\) \(AC^2 = 21625 - 4241.4 = 17383.6\) \(AC = \sqrt{17383.6} \approx 131.85\text{ m}\), which is \(132\text{ m}\) correct to 3 significant figures.
(b) Using the Sine Rule: \(\frac{\sin(ACB)}{AB} = \frac{\sin(ABC)}{AC}\) \(\frac{\sin(ACB)}{120} = \frac{\sin(78^\circ)}{131.85}\) \(\sin(ACB) = \frac{120 \times \sin(78^\circ)}{131.85} \approx 0.8902\) \(ACB = \arcsin(0.8902) \approx 62.9^\circ\).
(c) Area of the triangle: \(\text{Area} = \frac{1}{2} \times AB \times BC \times \sin(ABC)\) \(\text{Area} = \frac{1}{2} \times 120 \times 85 \times \sin(78^\circ) \approx 4988.55\text{ m}^2\), which is \(4990\text{ m}^2\) correct to 3 significant figures.
(d) The shortest distance from \(B\) to \(AC\) is the perpendicular height \(h\) of the triangle with base \(AC\). \(\text{Area} = \frac{1}{2} \times AC \times h\) \(4988.55 = \frac{1}{2} \times 131.85 \times h\) \(h = \frac{2 \times 4988.55}{131.85} \approx 75.67\text{ m}\), which is \(75.7\text{ m}\) correct to 3 significant figures.
PastPaper.markingScheme
(a) - M1: For \(120^2 + 85^2 - 2 \times 120 \times 85 \times \cos(78)\) - A1: For \(17383.6...\) - A1: For \(131.8...\) or \(132\)
(b) - M1: For \(\frac{\sin(ACB)}{120} = \frac{\sin(78)}{131.85}\) - M1: For rearranging to find \(\sin(ACB) = ...\) - A1: For \(62.9^\circ\) or \(62.88^\circ\)
(c) - M1: For \(\frac{1}{2} \times 120 \times 85 \times \sin(78)\) - A1: For \(4988.5...\) - A1: For \(4990\)
(d) - M1: For equating area formula to \(4988.5...\) or using \(85 \times \sin(62.9)\) - A1: For \(75.7\)
PastPaper.question 10 · Structured
11.82 PastPaper.marks
A solid toy is made by joining a cone of radius \(6\text{ cm}\) and height \(8\text{ cm}\) to a hemisphere of radius \(6\text{ cm}\) at its flat circular base.
(a) Show that the total volume of the solid is \(240\pi\text{ cm}^3\). [4]
(b) Calculate the total surface area of the solid (excluding the flat circular joint). Give your answer correct to 1 decimal place. [5]
(c) The solid is made of a metal with a density of \(7.8\text{ g/cm}^3\). Calculate the mass of the solid in kilograms, correct to 3 significant figures. [3]
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PastPaper.workedSolution
(a) The volume of the cone: \(V_{\text{cone}} = \frac{1}{3} \pi r^2 h = \frac{1}{3} \pi \times 6^2 \times 8 = 96\pi\text{ cm}^3\).
The volume of the hemisphere: \(V_{\text{hemi}} = \frac{2}{3} \pi r^3 = \frac{2}{3} \pi \times 6^3 = 144\pi\text{ cm}^3\).
Total volume: \(V_{\text{total}} = 96\pi + 144\pi = 240\pi\text{ cm}^3\).
(b) First find the slant height \(l\) of the cone: \(l = \sqrt{r^2 + h^2} = \sqrt{6^2 + 8^2} = 10\text{ cm}\).
Curved surface area of the cone: \(A_{\text{cone}} = \pi r l = \pi \times 6 \times 10 = 60\pi\text{ cm}^2\).
Curved surface area of the hemisphere: \(A_{\text{hemi}} = 2 \pi r^2 = 2 \pi \times 6^2 = 72\pi\text{ cm}^2\).
Total surface area: \(A_{\text{total}} = 60\pi + 72\pi = 132\pi \approx 414.69\text{ cm}^2\), which is \(414.7\text{ cm}^2\) correct to 1 decimal place.
(c) First find the total mass in grams: \(\text{Mass} = \text{Volume} \times \text{Density} = 240\pi \times 7.8 \approx 753.98 \times 7.8 = 5881.06\text{ g}\).
Convert to kilograms: \(\text{Mass} = \frac{5881.06}{1000} \approx 5.881\text{ kg}\), which is \(5.88\text{ kg}\) correct to 3 significant figures.
PastPaper.markingScheme
(a) - M1: For \(\frac{1}{3} \pi \times 6^2 \times 8\) - A1: For \(96\pi\) - M1: For \(\frac{2}{3} \pi \times 6^3\) - A1: For showing sum is \(240\pi\)
(b) - M1: For finding slant height \(l = \sqrt{6^2 + 8^2}\) - A1: For \(10\) - M1: For \(\pi \times 6 \times 10\) (or \(60\pi\)) - M1: For \(2 \pi \times 6^2\) (or \(72\pi\)) - A1: For \(414.7\)
(c) - M1: For multiplying \(240\pi\) (or \(754\)) by \(7.8\) - M1: For dividing by \(1000\) - A1: For \(5.88\)
PastPaper.question 11 · Structured
11.82 PastPaper.marks
A cyclist rides a distance of \(36\text{ km}\) at an average speed of \(x\text{ km/h}\). On her return journey, she increases her average speed by \(4\text{ km/h}\). The time taken for the return journey is \(45\text{ minutes}\) less than the time taken for the outward journey.
(a) Write down an expression, in terms of \(x\), for the time taken for the outward journey. [1]
(b) Write down an expression, in terms of \(x\), for the time taken for the return journey. [1]
(c) Form an equation in \(x\) and show that it simplifies to \(x^2 + 4x - 192 = 0\). [4]
(d) Solve the equation \(x^2 + 4x - 192 = 0\) to find the speed of the outward journey. [4]
(e) Find the total time taken for the entire round trip. [2]
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PastPaper.workedSolution
(a) Time taken for the outward journey = \(\frac{36}{x}\) hours.
(b) Speed for the return journey = \(x + 4\text{ km/h}\). Time taken for the return journey = \(\frac{36}{x + 4}\) hours.
(d) Factoring the quadratic equation: \(x^2 + 4x - 192 = 0\) We need two numbers that multiply to \(-192\) and add to \(4\). These numbers are \(+16\) and \(-12\). \((x + 16)(x - 12) = 0\) So \(x = -16\) or \(x = 12\). Since speed cannot be negative, \(x = 12\text{ km/h}\).
(e) Outward journey time = \(\frac{36}{12} = 3\text{ hours}\). Return journey time = \(\frac{36}{16} = 2.25\text{ hours}\). Total time = \(3 + 2.25 = 5.25\text{ hours}\) (or 5 hours 15 minutes).
PastPaper.markingScheme
(a) - B1: For \(\frac{36}{x}\)
(b) - B1: For \(\frac{36}{x + 4}\)
(c) - M1: For \(\frac{36}{x} - \frac{36}{x + 4} = 0.75\) (or \(\frac{3}{4}\) or \(45\)) - M1: For algebraic fraction common denominator conversion - M1: For expanding and eliminating fraction - A1: For showing clearly the final step leading to \(x^2 + 4x - 192 = 0\)
(d) - M1: For factorisation \((x+16)(x-12)\) or correct use of formula - A1: For solutions \(x = 12\) and \(x = -16\) - M1: For discarding negative root - A1: For final answer \(12\)
(e) - M1: For \(\frac{36}{12} + \frac{36}{16}\) - A1: For \(5.25\) hours (or 5h 15m)