An original Thinka practice paper modelled on the structure and difficulty of the Jun 2024 CCEA GCSE Mathematics 2210 paper. Not affiliated with or reproduced from CCEA.
Unit M4 Calculator Paper
Answer all twenty-three questions. Write your answers in the spaces provided. Complete in black ink. Calculator allowed.
23 Question · 100 marks
Question 1 · Standard procedural calculation
4 marks
A virus has diameter \( 3.2 \times 10^{-8} \) m and a bacterium has diameter \( 5.0 \times 10^{-6} \) m. (a) Calculate the diameter of the bacterium as a multiple of the diameter of the virus. Give your answer correct to 3 significant figures. (3) (b) The actual (unrounded) diameter of a second bacterium is \( 5.03 \times 10^{-6} \) m. Round this to 2 significant figures, in standard form. (1)
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Worked solution
(a) \( \dfrac{5.0 \times 10^{-6}}{3.2 \times 10^{-8}} = 156.25 \), which rounds to 156 (3 s.f.). (b) \( 5.03 \times 10^{-6} \) rounded to 2 significant figures is \( 5.0 \times 10^{-6} \) m.
Marking scheme
(a) M1: correct division set up \( 5.0\times10^{-6} \div 3.2\times10^{-8} \); A1: unrounded value 156.25 (or equivalent) seen; A1: 156 (3 s.f., ft from correct unrounded value). (b) A1: \( 5.0 \times 10^{-6} \) m correctly stated in standard form.
Question 2 · Standard procedural calculation
3 marks
Simplify \( \sqrt{50} - \sqrt{8} \), giving your answer in the form \( k\sqrt{2} \), where k is an integer.
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A charity shares a donation of £8400 between three projects in the ratio 3:4:5. Calculate the amount received by each project.
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Worked solution
Total parts = 3 + 4 + 5 = 12. Value of 1 part = \( 8400 \div 12 = £700 \). Amounts: \( 3 \times 700 = £2100 \); \( 4 \times 700 = £2800 \); \( 5 \times 700 = £3500 \).
Marking scheme
M1: total parts = 12 found; M1: value of 1 part = £700 found; A1: two of the three amounts correct; A1: all three amounts correct (£2100, £2800, £3500).
Question 4 · Standard procedural calculation
3 marks
It takes 5 workers 8 days to build a wall. Assuming all workers work at the same constant rate, calculate how many days it would take 4 workers to build the same wall.
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Worked solution
This is an inverse proportion problem. Total worker-days needed = \( 5 \times 8 = 40 \). With 4 workers: \( 40 \div 4 = 10 \) days.
Marking scheme
M1: total worker-days = 40 found (recognising inverse proportion); M1: 40 ÷ 4 set up; A1: 10 days.
Question 5 · Standard procedural calculation
3 marks
A savings account pays compound interest at 2.5% per annum. Sarah invests £3000. Calculate the total value of her investment after 3 years, giving your answer to the nearest penny.
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Worked solution
Using the compound interest multiplier \( 1.025 \): total value \( = 3000 \times 1.025^3 = 3000 \times 1.076890625 = £3230.67 \)... recalculated precisely: \( 3000 \times 1.025^3 = 3230.859... \), which rounds to £3230.86.
Marking scheme
M1: correct multiplier 1.025 used; M1: \( 3000 \times 1.025^3 \) calculated; A1: £3230.86 (accept values in the range £3230.85–£3230.86, depending on rounding method).
Question 6 · Standard procedural calculation
3 marks
A rectangle has length 8.4 cm (measured to the nearest 0.1 cm) and width 5.2 cm (measured to the nearest 0.1 cm). Calculate the upper bound for the area of the rectangle.
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Worked solution
Upper bound of length = 8.45 cm; upper bound of width = 5.25 cm. Upper bound of area \( = 8.45 \times 5.25 = 44.3625 \) cm² (accept 44.4 cm² to 3 s.f.).
Marking scheme
M1: upper bound length = 8.45 cm identified; M1: upper bound width = 5.25 cm identified; A1: 44.3625 cm² (accept 44.4 cm² to 3 s.f.).
Question 7 · Standard procedural calculation
3 marks
A garden path is made from rectangular slabs, each 0.6 m long and 0.4 m wide. Calculate the number of slabs needed to cover a path 12 m long and 2 m wide, assuming no wastage.
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Worked solution
Area of path \( = 12 \times 2 = 24 \) m². Area of one slab \( = 0.6 \times 0.4 = 0.24 \) m². Number of slabs \( = 24 \div 0.24 = 100 \).
Marking scheme
M1: area of path = 24 m² found; M1: area of one slab = 0.24 m² found; A1: 100 slabs.
Question 8 · Standard procedural calculation
3 marks
Expand and simplify \( (2x+3)(x-5) \).
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Solve the equation \( x^2 - 5x - 14 = 0 \) by factorising. Show all your working.
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Worked solution
We need two numbers that multiply to give -14 and add to give -5: these are -7 and 2. So \( x^2 - 5x - 14 = (x-7)(x+2) = 0 \). Setting each factor to zero: \( x = 7 \) or \( x = -2 \).
Marking scheme
M1: attempt to find factors of -14 summing to -5; M1: correct factorisation \( (x-7)(x+2) \); A1: x = 7; A1: x = -2; A1: both solutions clearly stated as the final answer.
The length of a rectangle is 3 cm more than its width. The area of the rectangle is 40 cm². Form an equation in terms of the width, w, and solve it to find the dimensions of the rectangle.
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Worked solution
Length = \( w+3 \). Area equation: \( w(w+3) = 40 \), so \( w^2 + 3w - 40 = 0 \). Factorising: \( (w+8)(w-5) = 0 \), giving \( w = 5 \) or \( w = -8 \). Since a width cannot be negative, \( w = -8 \) is rejected. So width = 5 cm, and length = \( 5+3 = 8 \) cm.
Marking scheme
M1: correct equation formed \( w(w+3)=40 \) or \( w^2+3w-40=0 \); M1: correct factorisation \( (w+8)(w-5) \) or correct use of the quadratic formula; A1: w = 5, with w = -8 correctly rejected and a reason given; A1: length = 8 cm; A1: both dimensions clearly stated with units.
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Worked solution
(a) \( 6x^2 - 24 = 6(x^2-4) = 6(x-2)(x+2) \), using the difference of two squares. (b) Setting \( 6(x-2)(x+2) = 0 \): since the factor 6 cannot be zero, either \( x-2=0 \) or \( x+2=0 \), giving \( x = 2 \) or \( x = -2 \).
Marking scheme
(a) M1: 6 taken out as a common factor, giving \( 6(x^2-4) \); A1: fully factorised \( 6(x-2)(x+2) \) (difference of two squares). (b) M1: sets each factor to zero; A1: x = 2; A1: x = -2.
Make x the subject of the formula \( y = \dfrac{3x+2}{x-1} \).
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Worked solution
Multiplying both sides by \( (x-1) \): \( y(x-1) = 3x+2 \), so \( yx - y = 3x + 2 \). Collecting x terms on one side: \( yx - 3x = y + 2 \). Factorising: \( x(y-3) = y+2 \). Dividing: \( x = \dfrac{y+2}{y-3} \).
Marking scheme
M1: multiplies both sides by (x-1) to clear the fraction; M1: expands to give \( yx - y = 3x + 2 \); M1: collects x terms on one side, \( yx - 3x = y+2 \); A1: factorises to \( x(y-3) = y+2 \); A1: \( x = \dfrac{y+2}{y-3} \).
Solve the simultaneous equations \( 3x + 2y = 16 \) and \( x - y = 2 \).
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Worked solution
From the second equation, \( x = y + 2 \). Substituting into the first equation: \( 3(y+2) + 2y = 16 \), so \( 3y + 6 + 2y = 16 \), giving \( 5y = 10 \), so \( y = 2 \). Then \( x = 2 + 2 = 4 \).
Marking scheme
M1: rearranges one equation to make x or y the subject (e.g. x = y+2); M1: correct substitution into the other equation; M1: correct simplification to solve for one variable (5y=10); A1: y = 2; A1: x = 4.
Question 15 · Statistical & probability problems
5 marks
The table shows the time taken (in minutes) by 60 students to complete a puzzle.
Time (min): 0≤t<10, frequency 8 Time (min): 10≤t<20, frequency 22 Time (min): 20≤t<30, frequency 18 Time (min): 30≤t<50, frequency 12
Calculate the frequency density for each class, and describe how a histogram representing this data should be constructed.
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Worked solution
Frequency density = frequency ÷ class width. For 0≤t<10 (width 10): \( 8 \div 10 = 0.8 \). For 10≤t<20 (width 10): \( 22 \div 10 = 2.2 \). For 20≤t<30 (width 10): \( 18 \div 10 = 1.8 \). For 30≤t<50 (width 20): \( 12 \div 20 = 0.6 \). A histogram would show frequency density on the vertical axis and time on the horizontal axis, with continuous bars (no gaps) drawn between the correct class boundaries at the heights calculated above.
Marking scheme
M1: correct class widths identified (10, 10, 10, 20); M1: frequency density formula (frequency ÷ width) applied to at least two classes; A1: two frequency densities correct; A1: all four frequency densities correct (0.8, 2.2, 1.8, 0.6); A1: correct description of histogram construction (frequency density on the y-axis, continuous bars matching class boundaries, no gaps).
Question 16 · Statistical & probability problems
5 marks
The cumulative frequency table shows the distribution of the masses (kg) of 80 parcels.
Mass < 5 kg: cumulative frequency 10 Mass < 10 kg: cumulative frequency 34 Mass < 15 kg: cumulative frequency 62 Mass < 20 kg: cumulative frequency 76 Mass < 25 kg: cumulative frequency 80
(a) Estimate the median mass, using linear interpolation. (2) (b) Estimate the interquartile range. (3)
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Worked solution
With n = 80: the median is the 40th value, which falls in the 10–15 kg class (cumulative frequency rises from 34 to 62 across this class of width 5 kg): \( \text{median} \approx 10 + \dfrac{40-34}{62-34}\times5 = 10+1.07 = 11.1 \) kg. The lower quartile is the 20th value, in the 5–10 kg class (cumulative frequency 10 to 34, width 5): \( Q_1 \approx 5 + \dfrac{20-10}{34-10}\times5 = 5+2.08 = 7.1 \) kg. The upper quartile is the 60th value, in the 10–15 kg class (cumulative frequency 34 to 62, width 5): \( Q_3 \approx 10 + \dfrac{60-34}{62-34}\times5 = 10+4.64 = 14.6 \) kg. Interquartile range \( = Q_3 - Q_1 \approx 14.6 - 7.1 = 7.6 \) kg (using unrounded intermediate values).
Marking scheme
(a) M1: correct linear interpolation method shown/identified within the correct class; A1: median ≈ 11.1 kg (accept 10.9–11.2). (b) M1: correct method for Q1 (≈ 7.1 kg); M1: correct method for Q3 (≈ 14.6 kg); A1: IQR ≈ 7.6 kg (accept 7.3–7.8, error carried forward from Q1/Q3).
Question 17 · Statistical & probability problems
4 marks
The table shows the number of goals scored by a football team in 20 matches.
Goals: 0, frequency 3 Goals: 1, frequency 6 Goals: 2, frequency 7 Goals: 3, frequency 3 Goals: 4, frequency 1
Calculate the mean number of goals scored per match.
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Worked solution
\( \Sigma(\text{goals} \times \text{frequency}) = (0\times3)+(1\times6)+(2\times7)+(3\times3)+(4\times1) = 0+6+14+9+4 = 33 \). Total number of matches = 20. \( \text{Mean} = 33 \div 20 = 1.65 \).
Marking scheme
M1: correct products calculated (0, 6, 14, 9, 4); M1: sum of products = 33; M1: total frequency = 20 identified; A1: mean = 1.65.
Question 18 · Statistical & probability problems
4 marks
A bag contains 5 red counters and 3 blue counters. Two counters are drawn at random, one after the other, without replacement. Calculate the probability that both counters are the same colour.
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M1: \( P(RR) = \dfrac{5}{8}\times\dfrac{4}{7} \) correctly calculated; M1: \( P(BB) = \dfrac{3}{8}\times\dfrac{2}{7} \) correctly calculated; M1: the two probabilities correctly added; A1: \( \dfrac{13}{28} \) (or equivalent, e.g. 0.464).
Question 19 · Geometry, trigonometry & circle theorems
6 marks
A ladder of length 6.5 m leans against a vertical wall, with its foot 2.5 m from the base of the wall on horizontal ground. (diagram not drawn accurately) (a) Calculate the height the ladder reaches up the wall. (3) (b) Calculate the angle the ladder makes with the ground, to 1 decimal place. (3)
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(a) M1: correct Pythagoras set up \( 6.5^2 - 2.5^2 \); M1: = 36; A1: height = 6.0 m. (b) M1: correct trig ratio set up (e.g. \( \cos\theta = 2.5/6.5 \) or \( \tan\theta = 6/2.5 \)); M1: correct inverse trig operation used; A1: 67.4° (1 d.p.).
Question 20 · Geometry, trigonometry & circle theorems
5 marks
In triangle ABC, angle B = 90°, AB = 8 cm and angle A = 35°. (diagram not drawn accurately) Calculate the length of BC, correct to 3 significant figures.
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Worked solution
Since angle A = 35° and BC is opposite A while AB is adjacent to A: \( \tan(35°) = \dfrac{BC}{AB} \), so \( BC = 8 \times \tan(35°) = 8 \times 0.70021 = 5.6017 \), which rounds to 5.60 cm (3 s.f.).
Marking scheme
M1: correct trigonometric ratio identified (\( \tan A = \text{opposite}/\text{adjacent} = BC/AB \)); M1: correct equation \( BC = 8\tan(35°) \) formed; A1: unrounded value ≈5.6017 seen; A1: 5.60 cm (3 s.f.).
Question 21 · Geometry, trigonometry & circle theorems
5 marks
A circle has a diameter of 14 cm. (a) Calculate the circumference of the circle, to 3 significant figures. (2) (b) Calculate the area of the circle, to 3 significant figures. (3)
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Worked solution
Radius = 7 cm. (a) \( C = \pi d = \pi \times 14 = 43.98 \), rounding to 44.0 cm (3 s.f.). (b) \( A = \pi r^2 = \pi \times 7^2 = \pi \times 49 = 153.94 \), rounding to 154 cm² (3 s.f.).
Marking scheme
(a) M1: \( C = \pi \times 14 \) set up; A1: 44.0 cm (3 s.f.). (b) M1: radius = 7 cm identified; M1: \( A = \pi \times 7^2 \) set up; A1: 154 cm² (3 s.f.).
Question 22 · Geometry, trigonometry & circle theorems
5 marks
A sector of a circle has radius 9 cm and angle at the centre 120°. (diagram not drawn accurately) Calculate the area of the sector, giving your answer to 3 significant figures.
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Worked solution
\( \text{Area of sector} = \dfrac{\theta}{360}\times\pi r^2 = \dfrac{120}{360}\times\pi\times9^2 = \dfrac{1}{3}\times254.47 = 84.82 \), which rounds to 84.8 cm² (3 s.f.).
Marking scheme
M1: correct fraction of circle identified (120/360 = 1/3); M1: full circle area calculated \( \pi \times 9^2 = 254.47 \); M1: correct formula applied (fraction × full area); A1: unrounded value ≈84.82; A1: 84.8 cm² (3 s.f.).
Question 23 · Geometry, trigonometry & circle theorems
5 marks
A swimming pool is in the shape of a cuboid, 25 m long, 10 m wide and 2 m deep. Calculate the volume of water needed to fill the pool completely, and state the volume in litres (1 m³ = 1000 litres).
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Answer all thirteen questions. You must not use a calculator for this paper. Show all working clearly.
13 Question · 50 marks
Question 1 · Linear inequalities and polygons
3 marks
Solve the inequality \( 3x - 7 \leq 2x + 5 \), and describe how your solution would be represented on a number line (state the type of circle and the direction of the arrow).
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Worked solution
\( 3x - 7 \leq 2x + 5 \); collecting x terms: \( 3x - 2x \leq 5 + 7 \), so \( x \leq 12 \). On a number line, this is represented with a closed (filled) circle at x = 12, since the inequality includes 12, with an arrow extending to the left, indicating all values less than or equal to 12.
Marking scheme
M1: correctly collects x terms on one side (\( 3x - 2x \leq 5+7 \) or equivalent); A1: x ≤ 12; A1: correct description of number line representation (closed circle at 12, arrow pointing left/towards negative values).
Question 2 · Linear inequalities and polygons
2 marks
Calculate the size of each interior angle of a regular octagon.
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Worked solution
Sum of interior angles of an n-sided polygon \( = (n-2)\times180° \); for an octagon, \( n=8 \): \( (8-2)\times180 = 1080° \). For a regular octagon, each interior angle \( = 1080 \div 8 = 135° \).
Triangle A has vertices at (1,1), (3,1) and (1,4). (a) Triangle A is rotated 90° clockwise about the origin to give triangle B. State the coordinates of the vertices of triangle B. (3) (b) Triangle A is enlarged by scale factor 2, centre (0,0), to give triangle C. State the coordinates of the vertices of triangle C. (2) (c) Describe fully the single transformation that maps triangle C back onto triangle A. (2)
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Worked solution
(a) Under a 90° clockwise rotation about the origin, \( (x,y) \to (y,-x) \). So \( (1,1)\to(1,-1) \); \( (3,1)\to(1,-3) \); \( (1,4)\to(4,-1) \). (b) Under enlargement scale factor 2 centre the origin, \( (x,y)\to(2x,2y) \). So \( (1,1)\to(2,2) \); \( (3,1)\to(6,2) \); \( (1,4)\to(2,8) \). (c) Since triangle C was formed from triangle A by an enlargement of scale factor 2 centre the origin, the inverse transformation mapping C back onto A is an enlargement, scale factor \( \dfrac{1}{2} \), centre (0,0).
Marking scheme
(a) M1: correct rotation rule applied \( (x,y)\to(y,-x) \); A1: two vertices correct; A1: all three vertices correct. (b) M1: correct enlargement rule \( (x,y)\to(2x,2y) \) applied; A1: all three vertices of C correct. (c) A1: enlargement identified with scale factor 1/2; A1: centre (0,0) stated.
Question 4 · Transformations and graphs
6 marks
A straight line passes through the points (2, 5) and (6, 13). (a) Calculate the gradient of the line. (2) (b) Find the equation of the line, in the form y = mx + c. (2) (c) A second line is parallel to this line and passes through (0, -3). State the equation of the second line. (2)
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Worked solution
(a) Gradient \( = \dfrac{13-5}{6-2} = \dfrac{8}{4} = 2 \). (b) Using \( y=mx+c \) with gradient 2 and the point (2,5): \( 5 = 2(2)+c \), so \( c=1 \); the equation is \( y=2x+1 \). (c) Parallel lines have the same gradient (2); using the point (0,-3), \( c=-3 \), giving \( y=2x-3 \).
Marking scheme
(a) M1: correct gradient formula set up; A1: gradient = 2. (b) M1: substitutes a point and the gradient into y=mx+c to find c; A1: y = 2x + 1. (c) M1: recognises parallel lines share the same gradient; A1: y = 2x - 3.
Question 5 · Simultaneous equations and combinations
4 marks
Solve the simultaneous equations \( y = x^2 - 2x \) and \( y = x + 4 \).
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Worked solution
Equating the expressions for y: \( x^2 - 2x = x + 4 \), so \( x^2 - 3x - 4 = 0 \). Factorising: \( (x-4)(x+1) = 0 \), giving \( x=4 \) or \( x=-1 \). When \( x=4 \): \( y = 4+4 = 8 \). When \( x=-1 \): \( y = -1+4 = 3 \).
Marking scheme
M1: correctly equates the two expressions and rearranges to \( x^2-3x-4=0 \); M1: correct factorisation \( (x-4)(x+1) \); A1: x = 4, y = 8; A1: x = -1, y = 3.
Question 6 · Simultaneous equations and combinations
3 marks
A fair six-sided dice is rolled twice. Calculate the probability of getting a total score of 9.
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Worked solution
The outcomes that sum to 9 are: (3,6), (4,5), (5,4), (6,3) — 4 outcomes. There are \( 6\times6=36 \) equally likely total outcomes. \( P(\text{total}=9) = \dfrac{4}{36} = \dfrac{1}{9} \).
Marking scheme
M1: total number of equally likely outcomes = 36 identified; M1: 4 favourable outcomes correctly listed/identified; A1: probability = 1/9 (accept 4/36 unsimplified, or equivalent decimal 0.111).
Question 7 · Number systems, similar shapes, surds & probability
4 marks
Two similar triangles, P and Q, have corresponding sides in the ratio 3:5. The area of triangle P is 27 cm². Calculate the area of triangle Q.
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Worked solution
Area scale factor \( = (\text{linear scale factor})^2 = \left(\dfrac{5}{3}\right)^2 = \dfrac{25}{9} \). Area of Q \( = 27 \times \dfrac{25}{9} = 75 \) cm².
Question 8 · Number systems, similar shapes, surds & probability
4 marks
In a class of 30 students, 18 study French, 15 study Spanish, and 7 study both French and Spanish. A student is chosen at random from the class. Calculate the probability that the student studies neither French nor Spanish.
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Worked solution
Using inclusion-exclusion, the number studying French or Spanish (or both) \( = 18+15-7 = 26 \). Number studying neither \( = 30-26 = 4 \). \( P(\text{neither}) = \dfrac{4}{30} = \dfrac{2}{15} \).
Marking scheme
M1: correct use of inclusion-exclusion \( (18+15-7) \); M1: = 26 correctly calculated; M1: \( 30-26=4 \) identified; A1: probability = 2/15 (or 4/30, accept equivalent decimal ≈0.133).
Question 9 · Number systems, similar shapes, surds & probability
4 marks
Solve \( x^2 + 6x + 5 = 0 \) by completing the square. Show all working.
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Worked solution
\( x^2+6x+5 = (x+3)^2 - 9 + 5 = (x+3)^2 - 4 \). Setting this to zero: \( (x+3)^2 = 4 \), so \( x+3 = \pm2 \), giving \( x=-1 \) or \( x=-5 \).
Marking scheme
M1: correctly completes the square, \( (x+3)^2 - 9 \); M1: simplifies to \( (x+3)^2 - 4 = 0 \) or \( (x+3)^2 = 4 \); A1: x = -1; A1: x = -5.
Question 10 · Number systems, similar shapes, surds & probability
4 marks
A ball is thrown upwards. Its height, h metres, above the ground after t seconds is given by \( h = 20t - 5t^2 \). Calculate the times at which the ball is at a height of 15 m.
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M1: correctly forms the equation \( 20t-5t^2=15 \); M1: rearranges and simplifies to \( t^2-4t+3=0 \); M1: correct factorisation \( (t-1)(t-3) \); A1: t = 1 s and t = 3 s both stated.
Question 11 · Number systems, similar shapes, surds & probability
3 marks
A ship sails 12 km due east, then 9 km due north. Calculate the direct distance of the ship from its starting point, correct to 1 decimal place.
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Worked solution
By Pythagoras: \( \text{distance} = \sqrt{12^2+9^2} = \sqrt{144+81} = \sqrt{225} = 15.0 \) km.
Marking scheme
M1: correct Pythagoras set up \( 12^2+9^2 \); M1: = 225; A1: 15.0 km.
Question 12 · Number systems, similar shapes, surds & probability
3 marks
A circle has centre O. A tangent to the circle touches the circle at point T, where OT = 5 cm. A point P outside the circle is such that OP = 13 cm, and PT is also a tangent to the circle. Using the fact that a tangent is perpendicular to the radius at the point of contact, calculate the length of PT.
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Worked solution
Since the tangent PT is perpendicular to the radius OT at T, triangle OTP is right-angled at T. By Pythagoras: \( PT = \sqrt{OP^2-OT^2} = \sqrt{13^2-5^2} = \sqrt{169-25} = \sqrt{144} = 12 \) cm.
Marking scheme
M1: recognises triangle OTP is right-angled at T (tangent-radius property); M1: correct Pythagoras set up \( 13^2-5^2 \); A1: PT = 12 cm.
Question 13 · Number systems, similar shapes, surds & probability
3 marks
A straight line has equation \( 2x + 3y = 12 \). Find the coordinates of the points where the line crosses the x-axis and the y-axis.
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Worked solution
When \( y=0 \): \( 2x=12 \), so \( x=6 \), giving the point (6,0). When \( x=0 \): \( 3y=12 \), so \( y=4 \), giving the point (0,4).
Marking scheme
M1: sets y = 0 and solves for x; A1: (6,0); A1: (0,4) with corresponding method for x = 0.
Unit M8 Paper 2 Calculator
Answer all twelve questions. Calculator permitted. Show all working clearly.
12 Question · 50 marks
Question 1 · Probability, indices & numerical approximations
3 marks
A student wants to investigate whether there is a link between the amount of time pupils spend on homework and their test scores. Describe a suitable method of data collection, including how a representative sample of pupils could be chosen.
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Worked solution
A suitable method would be to distribute a short questionnaire asking each pupil to record the average time (in minutes) spent on homework per week, alongside collecting their most recent test score from school records. To ensure the sample is representative of the whole school population, a stratified random sample should be used: pupils are selected from each year group (or class) in proportion to the size of that year group, with pupils within each stratum chosen using random sampling (e.g. random number generation), so that no particular year group or ability level is over- or under-represented.
Marking scheme
1 mark: a suitable, valid method of collecting the required data described (e.g. questionnaire/survey recording time and score); 1 mark: stratified sampling identified as the method for selecting a representative sample; 1 mark: correct explanation that the sample is stratified by an appropriate variable (e.g. year group) in proportion to population size, with random selection within each stratum.
Question 2 · Probability, indices & numerical approximations
3 marks
A cube has a volume of 216 cm³, measured to the nearest cm³. Calculate the lower bound for the length of one side of the cube, giving your answer correct to 3 significant figures.
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Worked solution
The lower bound of the volume, measured to the nearest cm³, is 215.5 cm³. The side length of the cube is \( \sqrt[3]{215.5} = 5.978 \), which rounds to 5.98 cm (3 s.f.).
Marking scheme
M1: lower bound of volume identified as 215.5 cm³; M1: cube root of 215.5 calculated; A1: 5.98 cm (3 s.f.).
Question 3 · Probability, indices & numerical approximations
2 marks
A spinner has 4 equal sections coloured red, blue, green and yellow. The spinner is spun twice. Calculate the probability of getting the same colour both times.
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Worked solution
\( P(\text{same colour}) = P(RR)+P(BB)+P(GG)+P(YY) = 4\times\left(\dfrac{1}{4}\times\dfrac{1}{4}\right) = 4\times\dfrac{1}{16} = \dfrac{1}{4} \). (Equivalently: whatever colour is spun first, the probability the second spin matches it is always 1/4.)
M1: both numerator and denominator correctly factorised; A1: correctly cancels the common factor to give \( \dfrac{x+3}{x+2} \).
Question 5 · Proportion, transformations & tree diagrams
4 marks
The variable y is directly proportional to the square of x. When x = 4, y = 48. (a) Find a formula for y in terms of x. (2) (b) Calculate the value of y when x = 6. (2)
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Worked solution
(a) \( y = kx^2 \). Substituting \( x=4, y=48 \): \( 48 = k(4^2) = 16k \), so \( k=3 \); the formula is \( y=3x^2 \). (b) \( y = 3(6^2) = 3\times36 = 108 \).
Marking scheme
(a) M1: correct proportional relationship set up (y=kx²) and substitution to find k; A1: \( y=3x^2 \). (b) M1: correct substitution x=6 into the formula; A1: y = 108.
Question 6 · Proportion, transformations & tree diagrams
4 marks
A shape has an area of 18 cm². The shape is enlarged by a scale factor of 2/3, centre the origin. (a) Calculate the area of the enlarged shape. (2) (b) State whether the enlarged shape is larger or smaller than the original shape, and explain your answer. (2)
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Worked solution
(a) Area scale factor \( = (2/3)^2 = 4/9 \); new area \( = 18 \times 4/9 = 8 \) cm². (b) The enlarged shape is smaller than the original, because a scale factor between 0 and 1 (here, 2/3) produces a reduction rather than an increase in size.
Marking scheme
(a) M1: area scale factor \( = (2/3)^2 = 4/9 \) identified; A1: 8 cm². (b) A1: smaller identified; A1: correct explanation that a scale factor between 0 and 1 produces a reduction.
Question 7 · Proportion, transformations & tree diagrams
3 marks
A bag contains only red and green marbles, from a total of 20 marbles. The probability of picking a red marble at random is 0.35. Two marbles are picked at random, one after the other, without replacement. Calculate the probability that both marbles picked are green.
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Worked solution
Since \( P(\text{red}) = 0.35 \), the number of red marbles \( = 0.35\times20 = 7 \), so the number of green marbles \( = 20-7 = 13 \). \( P(\text{both green}) = \dfrac{13}{20}\times\dfrac{12}{19} = \dfrac{156}{380} = \dfrac{39}{95} \approx 0.411 \).
Marking scheme
M1: number of green marbles = 13 correctly identified; M1: \( P(GG) = 13/20 \times 12/19 \) correctly set up; A1: 39/95 (or equivalent, e.g. 0.411, accept 156/380 unsimplified).
Question 8 · Advanced functions, tangents, rates & circle geometry
7 marks
A curve has equation \( y = x^3 - 3x^2 - 9x + 5 \). (a) Find \( \dfrac{dy}{dx} \). (2) (b) Find the coordinates of the two turning points on the curve, where the gradient is zero. (3) (c) Determine, with justification, whether each turning point is a maximum or a minimum. (2)
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Worked solution
(a) \( \dfrac{dy}{dx} = 3x^2-6x-9 \). (b) Setting \( 3x^2-6x-9=0 \): dividing by 3, \( x^2-2x-3=0 \), so \( (x-3)(x+1)=0 \), giving \( x=3 \) or \( x=-1 \). When \( x=-1 \): \( y=(-1)^3-3(-1)^2-9(-1)+5=-1-3+9+5=10 \). When \( x=3 \): \( y=27-27-27+5=-22 \). Turning points: (-1,10) and (3,-22). (c) \( \dfrac{d^2y}{dx^2}=6x-6 \). At \( x=-1 \): \( 6(-1)-6=-12<0 \), so (-1,10) is a maximum. At \( x=3 \): \( 6(3)-6=12>0 \), so (3,-22) is a minimum.
Marking scheme
(a) M1: correct differentiation of at least two terms; A1: \( 3x^2-6x-9 \). (b) M1: sets the derivative to zero and simplifies (e.g. \( x^2-2x-3=0 \)); M1: correct factorisation/solutions x=-1, x=3; A1: both coordinates correctly found ((-1,10) and (3,-22)). (c) M1: second derivative test (or valid alternative, e.g. sign change of gradient) correctly applied; A1: correctly identifies (-1,10) as a maximum and (3,-22) as a minimum.
Question 9 · Advanced functions, tangents, rates & circle geometry
7 marks
A curve has equation \( y = x^2 - 4x + 7 \). (a) Find the equation of the tangent to the curve at the point where x = 1. (4) (b) Find the coordinates of the point where this tangent crosses the x-axis. (3)
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Worked solution
(a) \( \dfrac{dy}{dx} = 2x-4 \); at \( x=1 \), gradient \( = 2(1)-4=-2 \). When \( x=1 \), \( y=1-4+7=4 \), so the point is (1,4). Equation of tangent: \( y-4=-2(x-1) \), so \( y=-2x+2+4=-2x+6 \). (b) The tangent crosses the x-axis when \( y=0 \): \( 0=-2x+6 \), so \( x=3 \), giving the point (3,0).
Marking scheme
(a) M1: correct differentiation \( dy/dx=2x-4 \); M1: gradient at x=1 correctly found (-2); M1: y-coordinate at x=1 correctly found (y=4); A1: correct tangent equation y = -2x + 6. (b) M1: sets y=0 in the tangent equation; A1: (3,0), with correct working shown.
Question 10 · Advanced functions, tangents, rates & circle geometry
7 marks
A chord AB of a circle with centre O has length 16 cm. The radius of the circle is 10 cm. (diagram not drawn accurately) (a) Calculate the perpendicular distance from O to the chord AB, giving your answer to 3 significant figures. (4) (b) Calculate the angle AOB, correct to 1 decimal place. (3)
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Worked solution
(a) The perpendicular from the centre to a chord bisects the chord, so half of AB = 8 cm. Using Pythagoras in the right-angled triangle formed by the radius, half-chord and perpendicular distance d: \( d = \sqrt{10^2-8^2} = \sqrt{100-64} = \sqrt{36} = 6.00 \) cm. (b) In the same right-angled triangle (hypotenuse 10 cm, opposite side to the half-angle = 8 cm): \( \sin(\theta/2) = \dfrac{8}{10} = 0.8 \), so \( \theta/2 = \sin^{-1}(0.8) = 53.13° \), giving angle AOB \( = 2\times53.13° = 106.3° \) (1 d.p.).
Marking scheme
(a) M1: recognises the perpendicular from the centre bisects the chord (half-chord = 8 cm); M1: correct Pythagoras set up \( 10^2-8^2 \); A1: unrounded value 6; A1: d = 6.00 cm. (b) M1: correct trig ratio set up for the half-angle (e.g. \( \sin(\theta/2)=8/10 \)); M1: \( \theta/2 = 53.13° \) found; A1: angle AOB = 106.3° (1 d.p., doubling correctly applied).
Question 11 · 3D trigonometry & Sine/Cosine applications
4 marks
A cuboid has length 12 cm, width 5 cm and height 4 cm. Calculate the length of the diagonal connecting opposite corners of the cuboid, giving your answer to 3 significant figures.
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Worked solution
The length of the space diagonal of a cuboid is given by \( d = \sqrt{l^2+w^2+h^2} = \sqrt{12^2+5^2+4^2} = \sqrt{144+25+16} = \sqrt{185} = 13.6 \) cm (3 s.f.).
Marking scheme
M1: correct 3D Pythagoras formula identified \( \sqrt{l^2+w^2+h^2} \); M1: correct substitution \( 12^2+5^2+4^2=185 \); A1: \( \sqrt{185} \) evaluated; A1: 13.6 cm (3 s.f.).
Question 12 · 3D trigonometry & Sine/Cosine applications
4 marks
A vertical flagpole stands at the top of a hill. From a point P on horizontal ground at the base of the hill, the angle of elevation to the bottom of the flagpole is 32° and the angle of elevation to the top of the flagpole is 38°. The horizontal distance from P to the point directly below the flagpole is 45 m. (diagram not drawn accurately) Calculate the height of the flagpole itself, correct to 3 significant figures.
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Worked solution
Height to the base of the flagpole \( = 45\tan(32°) = 45\times0.62487 = 28.12 \) m. Height to the top of the flagpole \( = 45\tan(38°) = 45\times0.78129 = 35.16 \) m. Height of the flagpole itself is the difference: \( 35.16-28.12 = 7.04 \) m (3 s.f., using unrounded intermediate values).
Marking scheme
M1: correct expression for height to the base of the flagpole (\( 45\tan32° \)); M1: correct expression for height to the top of the flagpole (\( 45\tan38° \)); M1: correctly subtracts the two heights to find the flagpole height alone; A1: 7.04 m (3 s.f., accept 7.03–7.04 depending on rounding).
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