Cambridge IGCSE · thinka-original Practice Paper

2026 Cambridge IGCSE Mathematics (0580) Practice Paper with Answers

Thinka Jun 2026 (V2) Cambridge IGCSE-Style Mock — Mathematics (0580)

200 marks240 mins2026
An original Thinka practice paper modelled on the structure and difficulty of the Jun 2026 (V2) Cambridge IGCSE Mathematics (0580) paper. Not affiliated with or reproduced from Cambridge.

Paper 2 Non-Calculator Extended

Answer all questions. Calculators must not be used. Show all necessary working clearly.
25 Question · 100 marks
Question 1 · short-answer
2.25 marks
Simplify \(\frac{18}{3 + \sqrt{3}}\), giving your answer in the form \(a + b\sqrt{3}\), where \(a\) and \(b\) are integers.
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Worked solution

Multiply numerator and denominator by the conjugate \(3 - \sqrt{3}\):
\[\frac{18(3 - \sqrt{3})}{(3 + \sqrt{3})(3 - \sqrt{3})} = \frac{18(3 - \sqrt{3})}{3^2 - (\sqrt{3})^2}\]
\[= \frac{18(3 - \sqrt{3})}{9 - 3} = \frac{18(3 - \sqrt{3})}{6}\]
\[= 3(3 - \sqrt{3}) = 9 - 3\sqrt{3}\]

Marking scheme

M1 for multiplying numerator and denominator by \(3 - \sqrt{3}\)
A1 for denominator correctly simplified to 6
A1 (or remaining mark fraction) for final answer \(9 - 3\sqrt{3}\)
Question 2 · short-answer
2.25 marks
Work out the value of \(\left(\frac{125}{64}\right)^{-\frac{2}{3}}\). Give your answer as a fraction in its simplest form.
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Worked solution

Apply the negative index to take the reciprocal:
\[\left(\frac{125}{64}\right)^{-\frac{2}{3}} = \left(\frac{64}{125}\right)^{\frac{2}{3}}\]
Take the cube root of numerator and denominator:
\[\left(\frac{\sqrt[3]{64}}{\sqrt[3]{125}}\right)^2 = \left(\frac{4}{5}\right)^2\]
Square the result:
\[\frac{4^2}{5^2} = \frac{16}{25}\]

Marking scheme

M1 for dealing with negative index or cube root correctly, e.g. \(\left(\frac{64}{125}\right)^{\frac{2}{3}}\) or \(\left(\frac{5}{4}\right)^{-2}\)
A1 for obtaining \(\frac{4}{5}\) before squaring
A1 (or remaining mark fraction) for \(\frac{16}{25}\) cao
Question 3 · short-answer
2.25 marks
Write the recurring decimal \(0.2\dot{4}\dot{5}\) as a fraction in its simplest form. You must show all your working.
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Worked solution

Let \(x = 0.2454545\dots\)
Multiply by 10: \(10x = 2.454545\dots\)
Multiply by 1000: \(1000x = 245.454545\dots\)
Subtract the two equations:
\[1000x - 10x = 245.4545\dots - 2.4545\dots\]
\[990x = 243\]
\[x = \frac{243}{990}\]
Divide numerator and denominator by 9:
\[x = \frac{27}{110}\]

Marking scheme

M1 for setting up equations such as \(1000x = 245.45\dots\) and \(10x = 2.45\dots\) or \(100x = 24.545\dots\)
M1 for subtraction to eliminate recurring part, e.g. \(990x = 243\) or \(99x = 24.3\)
A1 (or remaining mark fraction) for \(\frac{27}{110}\) in simplest form
Question 4 · short-answer
2.25 marks
Simplify fully \(\left(32x^{10}y^{-15}\right)^{\frac{2}{5}}\).
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Worked solution

Apply the power \(\frac{2}{5}\) to each component inside the bracket:
\[32^{\frac{2}{5}} = (\sqrt[5]{32})^2 = 2^2 = 4\]
\[(x^{10})^{\frac{2}{5}} = x^{10 \times \frac{2}{5}} = x^4\]
\[(y^{-15})^{\frac{2}{5}} = y^{-15 \times \frac{2}{5}} = y^{-6}\]
Combining these gives \(4x^4y^{-6}\) or \(\frac{4x^4}{y^6}\).

Marking scheme

B1 for numerical coefficient 4
B1 for \(x^4\) or \(y^{-6}\) (or \(y^6\) in denominator)
A1 (or remaining mark fraction) for fully correct expression \(4x^4y^{-6}\) or \(\frac{4x^4}{y^6}\)
Question 5 · short-answer
2.25 marks
Expand and simplify \((4\sqrt{3} - 1)(2\sqrt{3} + 5)\).
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Worked solution

Expand the brackets:
\[(4\sqrt{3})(2\sqrt{3}) + (4\sqrt{3})(5) - 1(2\sqrt{3}) - 1(5)\]
\[= (8 \times 3) + 20\sqrt{3} - 2\sqrt{3} - 5\]
\[= 24 + 18\sqrt{3} - 5\]
\[= 19 + 18\sqrt{3}\]

Marking scheme

M1 for correct expansion with at least 3 correct terms from \(24 + 20\sqrt{3} - 2\sqrt{3} - 5\)
A1 for correct like terms combined (e.g. 19 or \(18\sqrt{3}\))
A1 (or remaining mark fraction) for \(19 + 18\sqrt{3}\) or \(18\sqrt{3} + 19\)
Question 6 · short-answer
2.25 marks
Work out \(\frac{4.2 \times 10^7}{6 \times 10^{-3}}\). Give your answer in standard form.
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Worked solution

Divide the numerical coefficients and subtract the powers of 10:
\[\frac{4.2}{6} = 0.7\]
\[\frac{10^7}{10^{-3}} = 10^{7 - (-3)} = 10^{10}\]
Combine and adjust into standard form \(A \times 10^n\) where \(1 \le A < 10\):
\[0.7 \times 10^{10} = 7 \times 10^9\]

Marking scheme

M1 for \(0.7 \times 10^{10}\) or correct division step
A1 for adjusting correctly to standard form \(7 \times 10^9\)
SC1 for answer \(7000000000\) not in standard form
Question 7 · short-answer
2.25 marks
Work out \(3\frac{1}{5} \div 1\frac{7}{15} - \frac{5}{11}\). Give your answer as a fraction in its simplest form.
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Worked solution

Convert mixed numbers to improper fractions:
\[3\frac{1}{5} = \frac{16}{5}, \quad 1\frac{7}{15} = \frac{22}{15}\]
Perform division by multiplying by the reciprocal:
\[\frac{16}{5} \div \frac{22}{15} = \frac{16}{5} \times \frac{15}{22} = \frac{16 \times 3}{22} = \frac{48}{22} = \frac{24}{11}\]
Subtract the second fraction:
\[\frac{24}{11} - \frac{5}{11} = \frac{19}{11} \quad (\text{or } 1\frac{8}{11})\]

Marking scheme

M1 for improper fractions \(\frac{16}{5}\) and \(\frac{22}{15}\) and multiplying by reciprocal
A1 for \(\frac{24}{11}\) or equivalent fraction
A1 (or remaining mark fraction) for \(\frac{19}{11}\) or \(1\frac{8}{11}\) cao
Question 8 · short-answer
2.25 marks
Simplify \(\sqrt{75} - 2\sqrt{27} + \sqrt{108}\).
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Worked solution

Simplify each surd by extracting square factors:
\[\sqrt{75} = \sqrt{25 \times 3} = 5\sqrt{3}\]
\[2\sqrt{27} = 2\sqrt{9 \times 3} = 2 \times 3\sqrt{3} = 6\sqrt{3}\]
\[\sqrt{108} = \sqrt{36 \times 3} = 6\sqrt{3}\]
Combine the terms:
\[5\sqrt{3} - 6\sqrt{3} + 6\sqrt{3} = 5\sqrt{3}\]

Marking scheme

M1 for simplifying at least two surds correctly to terms in \(\sqrt{3}\) (e.g. \(5\sqrt{3}\), \(6\sqrt{3}\))
A1 for all three terms correctly simplified: \(5\sqrt{3} - 6\sqrt{3} + 6\sqrt{3}\)
A1 (or remaining mark fraction) for \(5\sqrt{3}\) cao
Question 9 · short_answer
4 marks
In triangle \(OAB\), \(\vec{OA} = \mathbf{a}\) and \(\vec{OB} = \mathbf{b}\).
\(P\) is the point on \(AB\) such that \(AP : PB = 2 : 3\).
\(M\) is the midpoint of \(OB\).

Find \(\vec{MP}\) in terms of \(\mathbf{a}\) and \(\mathbf{b}\). Give your answer in its simplest form.
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Worked solution

First, find \(\vec{AB}\):
\[\vec{AB} = \vec{OB} - \vec{OA} = \mathbf{b} - \mathbf{a}\]

Next, find the position vector of \(P\):
\[\vec{OP} = \vec{OA} + \frac{2}{5}\vec{AB} = \mathbf{a} + \frac{2}{5}(\mathbf{b} - \mathbf{a}) = \frac{3}{5}\mathbf{a} + \frac{2}{5}\mathbf{b}\]

Since \(M\) is the midpoint of \(OB\):
\[\vec{OM} = \frac{1}{2}\mathbf{b}\]

Now find \(\vec{MP}\):
\[\vec{MP} = \vec{OP} - \vec{OM} = \left(\frac{3}{5}\mathbf{a} + \frac{2}{5}\mathbf{b}\right) - \frac{1}{2}\mathbf{b}\]
\[\vec{MP} = \frac{3}{5}\mathbf{a} + \left(\frac{2}{5} - \frac{1}{2}\right)\mathbf{b} = \frac{3}{5}\mathbf{a} - \frac{1}{10}\mathbf{b}\]

Marking scheme

M1 for \(\vec{AB} = \mathbf{b} - \mathbf{a}\) or \(\vec{BA} = \mathbf{a} - \mathbf{b}\)
M1 for \(\vec{OP} = \mathbf{a} + \frac{2}{5}(\mathbf{b} - \mathbf{a})\) or \(\vec{MP} = \vec{MO} + \vec{OA} + \frac{2}{5}\vec{AB}\)
M1 for a correct unsimplified expression for \(\vec{MP}\) in terms of \(\mathbf{a}\) and \(\mathbf{b}\), e.g. \(-\frac{1}{2}\mathbf{b} + \mathbf{a} + \frac{2}{5}(\mathbf{b} - \mathbf{a})\)
A1 for \(\frac{3}{5}\mathbf{a} - \frac{1}{10}\mathbf{b}\) or \(\frac{6\mathbf{a} - \mathbf{b}}{10}\)
Question 10 · short_answer
3 marks
Triangle \(T\) has vertices at \((1, 2)\), \((3, 2)\) and \((3, 5)\).
Triangle \(U\) has vertices at \((-2, -1)\), \((-2, -3)\) and \((-5, -3)\).

Describe fully the single transformation that maps triangle \(T\) onto triangle \(U\).
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Worked solution

Observing the coordinates of corresponding vertices:
\((1, 2) \to (-2, -1)\)
\((3, 2) \to (-2, -3)\)
\((3, 5) \to (-5, -3)\)

Each point \((x, y)\) maps to \((-y, -x)\).
This is the standard matrix transformation \(\begin{pmatrix} 0 & -1 \\ -1 & 0 \end{pmatrix}\), which represents a reflection in the line \(y = -x\).

Marking scheme

B1 for Reflection
B2 for in the line \(y = -x\)
(Note: award 0 marks if more than one transformation is mentioned)
Question 11 · short_answer
4 marks
A curve has equation \(y = 2x^2 - 12x + 11\).

(a) Write \(2x^2 - 12x + 11\) in the form \(a(x + p)^2 + q\).
(b) Hence, write down the coordinates of the turning point of the curve.
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Worked solution

(a)
Factorise the coefficient of \(x^2\) from the first two terms:
\[2x^2 - 12x + 11 = 2(x^2 - 6x) + 11\]
Complete the square inside the bracket:
\[x^2 - 6x = (x - 3)^2 - 9\]
Substitute back:
\[2[(x - 3)^2 - 9] + 11 = 2(x - 3)^2 - 18 + 11 = 2(x - 3)^2 - 7\]

(b)
From the completed square form \(y = 2(x - 3)^2 - 7\), the minimum value occurs when \(x - 3 = 0 \implies x = 3\), giving \(y = -7\).
So the turning point is \((3, -7)\).

Marking scheme

(a)
B1 for \(a = 2\)
M1 for \((x - 3)^2\) seen in working
A1 for \(2(x - 3)^2 - 7\)

(b)
B1 FT for \((3, -7)\) from their \(a(x + p)^2 + q\)
Question 12 · short_answer
4 marks
Vector \(\mathbf{p} = \begin{pmatrix} 1 \\ -2 \end{pmatrix}\) and vector \(\mathbf{q} = \begin{pmatrix} k \\ 10 \end{pmatrix}\), where \(k\) is a positive constant.

The magnitude of the vector \(\mathbf{p} + \mathbf{q}\) is \(10\).

Work out the value of \(k\).
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Worked solution

First, find the sum vector \(\mathbf{p} + \mathbf{q}\):
\[\mathbf{p} + \mathbf{q} = \begin{pmatrix} 1 \\ -2 \end{pmatrix} + \begin{pmatrix} k \\ 10 \end{pmatrix} = \begin{pmatrix} k + 1 \\ 8 \end{pmatrix}\]

The magnitude of this vector is given by:
\[|\mathbf{p} + \mathbf{q}| = \sqrt{(k + 1)^2 + 8^2}\]

Given that the magnitude is \(10\):
\[\sqrt{(k + 1)^2 + 64} = 10\]
Square both sides:
\[(k + 1)^2 + 64 = 100\]
\[(k + 1)^2 = 36\]
Taking square roots:
\[k + 1 = 6 \quad \text{or} \quad k + 1 = -6\]
\[k = 5 \quad \text{or} \quad k = -7\]
Since \(k\) is positive, \(k = 5\).

Marking scheme

M1 for \(\mathbf{p} + \mathbf{q} = \begin{pmatrix} k + 1 \\ 8 \end{pmatrix}\)
M1 for \((k + 1)^2 + 8^2 = 10^2\) or \(\sqrt{(k + 1)^2 + 8^2} = 10\)
M1 for solving quadratic or taking square root: \((k + 1)^2 = 36 \implies k + 1 = \pm 6\)
A1 for \(k = 5\) only
Question 13 · short_answer
4 marks
Triangle \(A\) has vertices at \((2, 1)\), \((4, 1)\) and \((2, 5)\).

Triangle \(A\) is mapped onto triangle \(B\) by an enlargement with scale factor \(-\frac{1}{2}\) and centre \((0, 3)\).

Find the coordinates of the vertices of triangle \(B\).
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Worked solution

For an enlargement with centre \(C(x_0, y_0)\) and scale factor \(k = -\frac{1}{2}\), the image of a point \(P(x, y)\) is given by:
\[P' = C + k(P - C)\]
Here \(C = (0, 3)\).

1. For \((2, 1)\):
Vector from centre: \(\begin{pmatrix} 2 - 0 \\ 1 - 3 \end{pmatrix} = \begin{pmatrix} 2 \\ -2 \end{pmatrix}\)
Multiply by scale factor \(-\frac{1}{2}\): \(-\frac{1}{2}\begin{pmatrix} 2 \\ -2 \end{pmatrix} = \begin{pmatrix} -1 \\ 1 \end{pmatrix}\)
Image vertex: \(\begin{pmatrix} 0 \\ 3 \end{pmatrix} + \begin{pmatrix} -1 \\ 1 \end{pmatrix} = \begin{pmatrix} -1 \\ 4 \end{pmatrix}\)

2. For \((4, 1)\):
Vector from centre: \(\begin{pmatrix} 4 - 0 \\ 1 - 3 \end{pmatrix} = \begin{pmatrix} 4 \\ -2 \end{pmatrix}\)
Multiply by scale factor \(-\frac{1}{2}\): \(-\frac{1}{2}\begin{pmatrix} 4 \\ -2 \end{pmatrix} = \begin{pmatrix} -2 \\ 1 \end{pmatrix}\)
Image vertex: \(\begin{pmatrix} 0 \\ 3 \end{pmatrix} + \begin{pmatrix} -2 \\ 1 \end{pmatrix} = \begin{pmatrix} -2 \\ 4 \end{pmatrix}\)

3. For \((2, 5)\):
Vector from centre: \(\begin{pmatrix} 2 - 0 \\ 5 - 3 \end{pmatrix} = \begin{pmatrix} 2 \\ 2 \end{pmatrix}\)
Multiply by scale factor \(-\frac{1}{2}\): \(-\frac{1}{2}\begin{pmatrix} 2 \\ 2 \end{pmatrix} = \begin{pmatrix} -1 \\ -1 \end{pmatrix}\)
Image vertex: \(\begin{pmatrix} 0 \\ 3 \end{pmatrix} + \begin{pmatrix} -1 \\ -1 \end{pmatrix} = \begin{pmatrix} -1 \\ 2 \end{pmatrix}\)

The vertices of triangle \(B\) are \((-1, 4)\), \((-2, 4)\) and \((-1, 2)\).

Marking scheme

M1 for correctly calculating vectors from centre \((0, 3)\) to at least two vertices
M1 for multiplying vector displacements by \(-\frac{1}{2}\)
A1 for two correct vertices found
A1 for all three correct vertices: \((-1, 4)\), \((-2, 4)\), \((-1, 2)\)
Question 14 · short_answer
4 marks
The line segment joining \(A(-3, 8)\) and \(B(5, -4)\) has midpoint \(M\).

Find the equation of the perpendicular bisector of \(AB\).
Give your answer in the form \(y = mx + c\).
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Worked solution

1. Find the coordinates of the midpoint \(M\):
\[M = \left(\frac{-3 + 5}{2}, \frac{8 + (-4)}{2}\right) = (1, 2)\]

2. Find the gradient of the line \(AB\):
\[m_{AB} = \frac{-4 - 8}{5 - (-3)} = \frac{-12}{8} = -\frac{3}{2}\]

3. Find the gradient of the perpendicular line \(m_\perp\):
\[m_\perp = -\frac{1}{m_{AB}} = \frac{2}{3}\]

4. Use the point-slope formula with \(M(1, 2)\):
\[y - 2 = \frac{2}{3}(x - 1)\]
\[y = \frac{2}{3}x - \frac{2}{3} + 2\]
\[y = \frac{2}{3}x + \frac{4}{3}\]

Marking scheme

B1 for midpoint \((1, 2)\)
M1 for gradient of \(AB = -\frac{3}{2}\)
M1 for perpendicular gradient \(m = \frac{2}{3}\)
A1 for \(y = \frac{2}{3}x + \frac{4}{3}\) or \(y = \frac{2}{3}x + 1\frac{1}{3}\)
Question 15 · short_answer
4 marks
In the diagram, \(OABC\) is a parallelogram.
\(\vec{OA} = 6\mathbf{a}\) and \(\vec{OC} = 9\mathbf{c}\).
\(X\) is the point on \(AB\) such that \(AX : XB = 1 : 2\).
\(Y\) is the point on the line segment \(OB\) such that \(OY = \frac{1}{3}OB\).

(a) Express \(\vec{OY}\) and \(\vec{CX}\) in terms of \(\mathbf{a}\) and \(\mathbf{c}\).
(b) What geometrical relationship exists between the line segments \(OY\) and \(CX\)?
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Worked solution

(a)
In parallelogram \(OABC\), \(\vec{CB} = \vec{OA} = 6\mathbf{a}\) and \(\vec{AB} = \vec{OC} = 9\mathbf{c}\).

\[\vec{OB} = \vec{OA} + \vec{AB} = 6\mathbf{a} + 9\mathbf{c}\]
Since \(\vec{OY} = \frac{1}{3}\vec{OB}\):
\[\vec{OY} = \frac{1}{3}(6\mathbf{a} + 9\mathbf{c}) = 2\mathbf{a} + 3\mathbf{c}\]

For \(\vec{CX}\):
\(X\) divides \(AB\) in the ratio \(1 : 2\), so \(\vec{AX} = \frac{1}{3}\vec{AB} = \frac{1}{3}(9\mathbf{c}) = 3\mathbf{c}\).
\[\vec{OX} = \vec{OA} + \vec{AX} = 6\mathbf{a} + 3\mathbf{c}\]
\[\vec{CX} = \vec{OX} - \vec{OC} = (6\mathbf{a} + 3\mathbf{c}) - 9\mathbf{c} = 6\mathbf{a} - 6\mathbf{c}\]

(b)
Alternative relationship check:
If finding \(\vec{YX}\):
\[\vec{YX} = \vec{OX} - \vec{OY} = (6\mathbf{a} + 3\mathbf{c}) - (2\mathbf{a} + 3\mathbf{c}) = 4\mathbf{a}\]
Since \(\vec{YX} = 4\mathbf{a}\) and \(\vec{OA} = 6\mathbf{a}\), the line segment \(YX\) is parallel to \(OA\) (and \(CB\)) and has length \(\frac{2}{3}\) of \(OA\).

Marking scheme

M1 for \(\vec{OB} = 6\mathbf{a} + 9\mathbf{c}\)
A1 for \(\vec{OY} = 2\mathbf{a} + 3\mathbf{c}\)
M1 for \(\vec{OX} = 6\mathbf{a} + 3\mathbf{c}\) or \(\vec{CX} = \vec{CO} + \vec{OA} + \vec{AX}\)
A1 for \(\vec{CX} = 6\mathbf{a} - 6\mathbf{c}\)
Question 16 · short_answer
4 marks
A cyclist travels along a straight track.
The cyclist accelerates from rest at a constant rate for \(8\text{ s}\) to a speed of \(v\text{ m/s}\).
They then travel at this constant speed \(v\text{ m/s}\) for \(16\text{ s}\).
Finally, they decelerate at a constant rate for \(6\text{ s}\) to come to rest.

The total distance travelled by the cyclist is \(276\text{ m}\).

(a) Work out the value of \(v\).
(b) Work out the acceleration of the cyclist during the first \(8\text{ s}\).
Show answer & marking scheme

Worked solution

(a)
The speed-time graph forms a trapezium with parallel sides of length:
Top base = \(16\text{ s}\) (constant speed section)
Bottom base = \(8 + 16 + 6 = 30\text{ s}\) (total time)
Height = \(v\text{ m/s}\)

The area under the speed-time graph represents the total distance travelled:
\[\text{Distance} = \frac{1}{2} \times (16 + 30) \times v = 276\]
\[\frac{1}{2} \times 46 \times v = 276\]
\[23v = 276\]
\[v = \frac{276}{23} = 12\]

(b)
Acceleration is the gradient of the speed-time graph during the first \(8\text{ s}\):
\[\text{Acceleration} = \frac{v - 0}{8 - 0} = \frac{12}{8} = 1.5\text{ m/s}^2\]

Marking scheme

(a)
M1 for total time \(8 + 16 + 6 = 30\)
M1 for area formula: \(\frac{1}{2}(16 + 30)v = 276\) or sum of three sections \(\frac{1}{2}(8)(v) + 16v + \frac{1}{2}(6)(v) = 276\)
A1 for \(v = 12\)

(b)
B1 FT for \(\frac{\text{their } v}{8} = 1.5\)
Question 17 · short-answer
4 marks
In triangle \(OAB\), \(\vec{OA} = \mathbf{a}\) and \(\vec{OB} = \mathbf{b}\).
\(X\) is the point on the line segment \(AB\) such that \(AX : XB = 2 : 1\).

(a) Find \(\vec{AX}\) in terms of \(\mathbf{a}\) and \(\mathbf{b}\) in its simplest form. [2]

(b) The point \(Y\) has position vector \(\vec{OY} = 2\mathbf{b} - \mathbf{a}\).
Show that the points \(A\), \(X\) and \(Y\) lie on a straight line. [2]
Show answer & marking scheme

Worked solution

(a)
\(\vec{AB} = \vec{OB} - \vec{OA} = \mathbf{b} - \mathbf{a}\)
Since \(AX : XB = 2 : 1\), \(\vec{AX} = \frac{2}{3}\vec{AB}\).
\(\vec{AX} = \frac{2}{3}(\mathbf{b} - \mathbf{a})\) or \(-\frac{2}{3}\mathbf{a} + \frac{2}{3}\mathbf{b}\)

(b)
\(\vec{AY} = \vec{OY} - \vec{OA} = (2\mathbf{b} - \mathbf{a}) - \mathbf{a} = 2\mathbf{b} - 2\mathbf{a} = 2(\mathbf{b} - \mathbf{a})\)
Comparing \(\vec{AY}\) and \(\vec{AX}\):
\(\vec{AY} = 2(\mathbf{b} - \mathbf{a}) = 3 \times \left(\frac{2}{3}(\mathbf{b} - \mathbf{a})\right) = 3\vec{AX}\)
Since \(\vec{AY}\) is a scalar multiple of \(\vec{AX}\) (they are parallel) and both vectors share the common point \(A\), the points \(A\), \(X\) and \(Y\) lie on a straight line.

Marking scheme

(a)
M1 for \(\vec{AB} = \mathbf{b} - \mathbf{a}\) or for \(\frac{2}{3}\vec{AB}\) seen
A1 for \(\frac{2}{3}(\mathbf{b} - \mathbf{a})\) or \(-\frac{2}{3}\mathbf{a} + \frac{2}{3}\mathbf{b}\)

(b)
M1 for finding \(\vec{AY} = 2\mathbf{b} - 2\mathbf{a}\) or \(\vec{XY} = \frac{4}{3}\mathbf{b} - \frac{4}{3}\mathbf{a}\)
A1 for demonstrating scalar relationship (e.g. \(\vec{AY} = 3\vec{AX}\) or \(\vec{XY} = 2\vec{AX}\)) AND stating that they share a common point (e.g. \(A\) or \(X\))
Question 18 · short-answer
4 marks
Triangle \(A\) has vertices at \((1, 2)\), \((4, 2)\) and \((4, 4)\).

(a) Triangle \(A\) is mapped onto triangle \(B\) by a reflection in the line \(y = -x\).
Find the coordinates of the three vertices of triangle \(B\). [2]

(b) Triangle \(A\) is mapped onto triangle \(C\) with vertices at \((-2, -4)\), \((-8, -4)\) and \((-8, -8)\).
Describe fully the single transformation that maps triangle \(A\) onto triangle \(C\). [2]
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Worked solution

(a)
Reflection in the line \(y = -x\) maps each point \((x, y)\) to \((-y, -x)\):
- \((1, 2) \to (-2, -1)\)
- \((4, 2) \to (-2, -4)\)
- \((4, 4) \to (-4, -4)\)

(b)
Comparing coordinates of \(A\) and \(C\):
- \((1, 2) \to (-2, -4)\)
- \((4, 2) \to (-8, -4)\)
- \((4, 4) \to (-8, -8)\)
Each coordinate of triangle \(A\) is multiplied by \(-2\).
This is an enlargement with scale factor \(-2\) and centre of enlargement \((0, 0)\).

Marking scheme

(a)
B2 for all three correct coordinates: \((-2, -1)\), \((-2, -4)\), \((-4, -4)\)
(B1 for two correct pairs of coordinates or for reflection in \(y = x\) giving \((2, 1)\), \((2, 4)\), \((4, 4)\))

(b)
B1 for Enlargement
B1 for scale factor \(-2\) and centre \((0, 0)\) or origin
(Note: Award 0 marks if more than one transformation is mentioned)
Question 19 · Extended Non-linear / Calculus / Geometric Proof
6 marks
The equation of a curve is \(y = 2x^3 - 9x^2 + 12x - 5\).

(a) Find \(\frac{\mathrm{d}y}{\mathrm{d}x}\). [2]

(b) Find the coordinates of the two stationary points of the curve. [3]

(c) Determine the nature of the stationary point with the smaller \(x\)-coordinate. Give a reason for your answer. [1]
Show answer & marking scheme

Worked solution

(a)
Differentiating term by term with respect to \(x\):
\(\frac{\mathrm{d}y}{\mathrm{d}x} = 2(3x^2) - 9(2x) + 12(1) - 0 = 6x^2 - 18x + 12\)

(b)
At stationary points, \(\frac{\mathrm{d}y}{\mathrm{d}x} = 0\):
\(6x^2 - 18x + 12 = 0\)
Divide through by 6:
\(x^2 - 3x + 2 = 0\)
\((x - 1)(x - 2) = 0\)
So \(x = 1\) or \(x = 2\).

When \(x = 1\):
\(y = 2(1)^3 - 9(1)^2 + 12(1) - 5 = 2 - 9 + 12 - 5 = 0\)
First point: \((1, 0)\)

When \(x = 2\):
\(y = 2(2)^3 - 9(2)^2 + 12(2) - 5 = 16 - 36 + 24 - 5 = -1\)
Second point: \((2, -1)\)

(c)
The stationary point with the smaller \(x\)-coordinate is \((1, 0)\).
Using the second derivative:
\(\frac{\mathrm{d}^2y}{\mathrm{d}x^2} = 12x - 18\)
At \(x = 1\), \(\frac{\mathrm{d}^2y}{\mathrm{d}x^2} = 12(1) - 18 = -6\).
Since \(\frac{\mathrm{d}^2y}{\mathrm{d}x^2} < 0\), the point \((1, 0)\) is a local maximum.

Marking scheme

(a)
M1 for differentiating at least two terms correctly from \(2x^3 - 9x^2 + 12x - 5\)
A1 for \(6x^2 - 18x + 12\) or fully correct equivalent

(b)
M1 for setting their \(\frac{\mathrm{d}y}{\mathrm{d}x} = 0\) and attempting to solve the quadratic (by factorisation or formula)
A1 for \(x = 1\) and \(x = 2\)
A1 for both pairs of coordinates correct: \((1, 0)\) and \((2, -1)\)

(c)
B1 for Maximum with valid reason (e.g. \(\frac{\mathrm{d}^2y}{\mathrm{d}x^2} = 12(1) - 18 = -6 < 0\) or gradient changes from positive to negative through \(x = 1\))
Question 20 · Extended Non-linear / Calculus / Geometric Proof
6 marks
In triangle \(OAB\), \(\vec{OA} = \mathbf{a}\) and \(\vec{OB} = \mathbf{b}\).
\(P\) is the point on \(OA\) such that \(OP : PA = 3 : 1\).
\(M\) is the midpoint of \(AB\).
The line segment \(PM\) is extended to a point \(N\) such that \(\vec{PN} = 3\vec{PM}\).

(a) Express \(\vec{PM}\) in terms of \(\mathbf{a}\) and \(\mathbf{b}\) in its simplest form. [3]

(b) Express \(\vec{ON}\) in terms of \(\mathbf{a}\) and \(\mathbf{b}\) in its simplest form. [2]

(c) Hence, explain what your answer to part (b) shows about the points \(O\), \(B\) and \(N\). [1]
Show answer & marking scheme

Worked solution

(a)
Since \(OP : PA = 3 : 1\), \(\vec{OP} = \frac{3}{4}\vec{OA} = \frac{3}{4}\mathbf{a}\).
\(M\) is the midpoint of \(AB\):
\(\vec{AB} = \vec{OB} - \vec{OA} = \mathbf{b} - \mathbf{a}\)
\(\vec{OM} = \vec{OA} + \frac{1}{2}\vec{AB} = \mathbf{a} + \frac{1}{2}(\mathbf{b} - \mathbf{a}) = \frac{1}{2}\mathbf{a} + \frac{1}{2}\mathbf{b}\)

Then:
\(\vec{PM} = \vec{PO} + \vec{OM} = -\frac{3}{4}\mathbf{a} + \left(\frac{1}{2}\mathbf{a} + \frac{1}{2}\mathbf{b}\right) = -\frac{1}{4}\mathbf{a} + \frac{1}{2}\mathbf{b}\)

(b)
\(\vec{PN} = 3\vec{PM} = 3\left(-\frac{1}{4}\mathbf{a} + \frac{1}{2}\mathbf{b}\right) = -\frac{3}{4}\mathbf{a} + \frac{3}{2}\mathbf{b}\)

Now find \(\vec{ON}\):
\(\vec{ON} = \vec{OP} + \vec{PN} = \frac{3}{4}\mathbf{a} + \left(-\frac{3}{4}\mathbf{a} + \frac{3}{2}\mathbf{b}\right) = \frac{3}{2}\mathbf{b}\)

(c)
\(\vec{ON} = \frac{3}{2}\mathbf{b} = \frac{3}{2}\vec{OB}\).
This shows that \(\vec{ON}\) is a scalar multiple of \(\vec{OB}\) and both vectors start at the common point \(O\). Therefore, the points \(O\), \(B\) and \(N\) lie on a straight line (are collinear).

Marking scheme

(a)
B1 for \(\vec{OP} = \frac{3}{4}\mathbf{a}\) or \(\vec{OM} = \frac{1}{2}\mathbf{a} + \frac{1}{2}\mathbf{b}\)
M1 for \(\vec{PM} = -\vec{OP} + \vec{OM}\) or \(\vec{PA} + \vec{AM}\)
A1 for \(-\frac{1}{4}\mathbf{a} + \frac{1}{2}\mathbf{b}\) or \(\frac{1}{4}(2\mathbf{b} - \mathbf{a})\)

(b)
M1 for \(\vec{ON} = \vec{OP} + 3\vec{PM}\) substituted correctly
A1 for \(\frac{3}{2}\mathbf{b}\) or \(1.5\mathbf{b}\)

(c)
B1 for stating that \(O, B, N\) are collinear / lie on a straight line because \(\vec{ON}\) is a scalar multiple of \(\vec{OB}\) with common point \(O\) (or equivalent clear justification)
Question 21 · Extended Non-linear / Calculus / Geometric Proof
6 marks
\(A\), \(B\), \(C\) and \(D\) are points on the circumference of a circle, centre \(O\).
\(TA\) and \(TB\) are tangents to the circle at \(A\) and \(B\) respectively.
Angle \(ATB = 44^\circ\).

(a) Calculate angle \(AOB\). Give a reason for each step of your working. [2]

(b) Calculate angle \(ADB\). Give a geometric reason for your answer. [2]

(c) Given that \(ABCD\) is a cyclic quadrilateral, calculate angle \(BCD\). Give a geometric reason for your answer. [2]
Show answer & marking scheme

Worked solution

(a)
Angle \(OAT = 90^\circ\) and angle \(OBT = 90^\circ\) because the angle between a tangent and a radius is \(90^\circ\).
In quadrilateral \(OATB\), the sum of angles is \(360^\circ\):
Angle \(AOB = 360^\circ - 90^\circ - 90^\circ - 44^\circ = 136^\circ\).

(b)
Angle \(ADB = \frac{1}{2} \times \text{Angle } AOB = \frac{1}{2} \times 136^\circ = 68^\circ\).
Reason: The angle subtended by an arc at the centre is twice the angle subtended by it at the circumference.

(c)
In cyclic quadrilateral \(ABCD\), opposite angles sum to \(180^\circ\):
Angle \(BCD = 180^\circ - \text{Angle } ADB = 180^\circ - 68^\circ = 112^\circ\).
Reason: Opposite angles of a cyclic quadrilateral sum to \(180^\circ\).

Marking scheme

(a)
B1 for \(136^\circ\)
B1 for stating: tangent is perpendicular to radius / angle between tangent and radius is \(90^\circ\) AND angles in a quadrilateral add to \(360^\circ\)

(b)
B1 for \(68^\circ\) (or FT \(\frac{1}{2} \times \text{their } AOB\))
B1 for reason: angle at the centre is twice the angle at the circumference

(c)
B1 for \(112^\circ\) (or FT \(180^\circ - \text{their } ADB\))
B1 for reason: opposite angles of a cyclic quadrilateral add up to \(180^\circ\)
Question 22 · Extended Non-linear / Calculus / Geometric Proof
6 marks
Solve the simultaneous equations:
\[y - 2x = 1\]
\[x^2 + xy = 10\]
Show all your working. [6]
Show answer & marking scheme

Worked solution

From the linear equation:
\(y = 2x + 1\)

Substitute \(y = 2x + 1\) into the non-linear equation:
\(x^2 + x(2x + 1) = 10\)
\(x^2 + 2x^2 + x = 10\)
\(3x^2 + x - 10 = 0\)

Factorise the quadratic:
\((3x - 5)(x + 2) = 0\)

So:
\(3x - 5 = 0 \implies x = \frac{5}{3}\)
\(x + 2 = 0 \implies x = -2\)

Now find corresponding \(y\)-values using \(y = 2x + 1\):
When \(x = -2\):
\(y = 2(-2) + 1 = -4 + 1 = -3\)

When \(x = \frac{5}{3}\):
\(y = 2\left(\frac{5}{3}\right) + 1 = \frac{10}{3} + \frac{3}{3} = \frac{13}{3}\)

The solutions are \(x = -2, y = -3\) and \(x = \frac{5}{3}, y = \frac{13}{3}\).

Marking scheme

M1 for rearranging linear equation to make \(y\) (or \(x\)) the subject, e.g. \(y = 2x + 1\)
M1 for substituting their expression into the second equation to form an equation in one variable
A1 for correct 3-term quadratic equal to zero: \(3x^2 + x - 10 = 0\)
M1 for factorising their 3-term quadratic, e.g. \((3x - 5)(x + 2) = 0\), or correct use of quadratic formula
A1 for \(x = -2\) and \(x = \frac{5}{3}\) (or \(1\frac{2}{3}\))
A1 for \(y = -3\) and \(y = \frac{13}{3}\) (or \(4\frac{1}{3}\)) correctly paired
Question 23 · Extended Non-linear / Calculus / Geometric Proof
6 marks
A curve has equation \(y = 4x + \frac{9}{x}\) for \(x > 0\).

(a) Find \(\frac{\mathrm{d}y}{\mathrm{d}x}\). [2]

(b) Find the coordinates of the point on the curve where the gradient of the tangent is \(3\). [3]

(c) Find the minimum value of \(y\) for \(x > 0\). [1]
Show answer & marking scheme

Worked solution

(a)
Rewrite \(y\) as \(y = 4x + 9x^{-1}\).
Differentiating with respect to \(x\):
\(\frac{\mathrm{d}y}{\mathrm{d}x} = 4 + 9(-1)x^{-2} = 4 - 9x^{-2} = 4 - \frac{9}{x^2}\)

(b)
Set \(\frac{\mathrm{d}y}{\mathrm{d}x} = 3\):
\(4 - \frac{9}{x^2} = 3\)
\(1 = \frac{9}{x^2}\)
\(x^2 = 9\)
Since \(x > 0\), \(x = 3\).

Find the \(y\)-coordinate:
\(y = 4(3) + \frac{9}{3} = 12 + 3 = 15\)
Coordinates are \((3, 15)\).

(c)
At the minimum stationary point, \(\frac{\mathrm{d}y}{\mathrm{d}x} = 0\):
\(4 - \frac{9}{x^2} = 0 \implies x^2 = \frac{9}{4} \implies x = \frac{3}{2}\) (as \(x > 0\)).

Substitute \(x = \frac{3}{2}\) into \(y\):
\(y = 4\left(\frac{3}{2}\right) + \frac{9}{\frac{3}{2}} = 6 + 6 = 12\)
Minimum value of \(y\) is 12.

Marking scheme

(a)
M1 for derivative of form \(4 + k x^{-2}\) where \(k \ne 0\)
A1 for \(4 - 9x^{-2}\) or \(4 - \frac{9}{x^2}\)

(b)
M1 for setting their derivative equal to 3
M1 for solving to get \(x = 3\) (rejecting \(x = -3\))
A1 for \((3, 15)\)

(c)
B1 for 12
Question 24 · Extended Non-linear / Calculus / Geometric Proof
7 marks
In triangle \(PQR\), \(PQ = (x + 3)\text{ cm}\), \(QR = (2x - 1)\text{ cm}\) and angle \(PQR = 150^\circ\).
The area of triangle \(PQR\) is \(6.5\text{ cm}^2\).

(a) Show that \(2x^2 + 5x - 29 = 0\). [3]

(b) Solve the equation \(2x^2 + 5x - 29 = 0\), giving your answers in the exact form \(\frac{p \pm \sqrt{q}}{r}\), where \(p, q\) and \(r\) are integers. [3]

(c) State, with a reason, which value of \(x\) is the valid solution for the side lengths of the triangle. [1]
Show answer & marking scheme

Worked solution

(a)
Using the formula for the area of a triangle:
\(\text{Area} = \frac{1}{2} a b \sin C\)
\(\text{Area} = \frac{1}{2} (x + 3)(2x - 1) \sin(150^\circ)\)

Since \(\sin(150^\circ) = \sin(30^\circ) = \frac{1}{2}\):
\(6.5 = \frac{1}{2}(x + 3)(2x - 1)\left(\frac{1}{2}\right)\)
\(6.5 = \frac{1}{4}(2x^2 - x + 6x - 3)\)
\(6.5 = \frac{1}{4}(2x^2 + 5x - 3)\)
Multiply by 4:
\(26 = 2x^2 + 5x - 3\)
\(2x^2 + 5x - 29 = 0\)

(b)
Using the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\) with \(a = 2, b = 5, c = -29\):
\(x = \frac{-5 \pm \sqrt{5^2 - 4(2)(-29)}}{2(2)}\)
\(x = \frac{-5 \pm \sqrt{25 + 232}}{4}\)
\(x = \frac{-5 \pm \sqrt{257}}{4}\)

(c)
Since \(\sqrt{257} > \sqrt{256} = 16\), \(\frac{-5 - \sqrt{257}}{4} < \frac{-5 - 16}{4} = -5.25 < 0\).
A negative value of \(x\) would make side length \(QR = 2x - 1 < 0\), which is impossible for a geometrical length. Therefore, the only valid solution is \(x = \frac{-5 + \sqrt{257}}{4}\).

Marking scheme

(a)
M1 for substituting into area formula: \(\frac{1}{2}(x + 3)(2x - 1)\sin(150^\circ) = 6.5\)
M1 for using \(\sin(150^\circ) = \frac{1}{2}\) and expanding brackets: \(2x^2 + 5x - 3\)
A1 for completing all algebraic steps clearly to reach \(2x^2 + 5x - 29 = 0\) with no steps omitted

(b)
M1 for correct substitution into quadratic formula: \(\frac{-5 \pm \sqrt{5^2 - 4(2)(-29)}}{2(2)}\)
M1 for simplifying the discriminant: \(25 + 232 = 257\)
A1 for \(\frac{-5 \pm \sqrt{257}}{4}\)

(c)
B1 for choosing \(x = \frac{-5 + \sqrt{257}}{4}\) with correct geometric reason (side lengths must be positive / lengths cannot be negative)
Question 25 · Extended Non-linear / Calculus / Geometric Proof
6 marks
The function \(\mathrm{f}\) is defined by \(\mathrm{f}(x) = 2x^2 - 12x + 13\) for \(x \ge 3\).

(a) Express \(\mathrm{f}(x)\) in the form \(a(x - h)^2 + k\), where \(a, h\) and \(k\) are integers. [3]

(b) State the range of \(\mathrm{f}\). [1]

(c) Find an expression for \(\mathrm{f}^{-1}(x)\). [2]
Show answer & marking scheme

Worked solution

(a)
Factorise 2 from the \(x\)-terms:
\(\mathrm{f}(x) = 2(x^2 - 6x) + 13\)

Complete the square inside the bracket:
\(x^2 - 6x = (x - 3)^2 - 3^2 = (x - 3)^2 - 9\)

Substitute back:
\(\mathrm{f}(x) = 2[(x - 3)^2 - 9] + 13\)
\(\mathrm{f}(x) = 2(x - 3)^2 - 18 + 13\)
\(\mathrm{f}(x) = 2(x - 3)^2 - 5\)

(b)
Since \(x \ge 3\), \((x - 3)^2 \ge 0\).
The minimum value occurs at \(x = 3\) where \(\mathrm{f}(3) = -5\).
Hence the range is \(\mathrm{f}(x) \ge -5\) (or \(y \ge -5\)).

(c)
Let \(y = 2(x - 3)^2 - 5\) for \(x \ge 3\):
\(y + 5 = 2(x - 3)^2\)
\(\frac{y + 5}{2} = (x - 3)^2\)

Take the positive square root since \(x \ge 3\):
\(x - 3 = \sqrt{\frac{y + 5}{2}}\)
\(x = 3 + \sqrt{\frac{y + 5}{2}}\)

Therefore:
\(\mathrm{f}^{-1}(x) = 3 + \sqrt{\frac{x + 5}{2}}\)

Marking scheme

(a)
B1 for \(a = 2\)
M1 for \((x - 3)^2\)
A1 for \(2(x - 3)^2 - 5\)

(b)
B1 for \(\mathrm{f}(x) \ge -5\) or \(y \ge -5\) (accept \([-5, \infty)\))

(c)
M1 for correctly rearranging their \(y = a(x - h)^2 + k\) to make \((x - h)^2\) the subject
A1 for \(3 + \sqrt{\frac{x + 5}{2}}\) (must be in terms of \(x\) and positive square root)

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Practise This Topic

Paper 4 Calculator Extended

Answer all questions. A scientific calculator should be used. Give answers to 3 significant figures or 1 decimal place for angles unless specified.
22 Question · 100 marks
Question 1 · short-answer
3 marks
The value of a car depreciates at a constant rate of 12% per year.
After 3 years, the value of the car is $11\,585.12.

Calculate the original value of the car.
Show answer & marking scheme

Worked solution

Let the original value of the car be \(P\).

Using the formula for compound depreciation:
\[ V = P(1 - r)^n \]
\[ 11\,585.12 = P(1 - 0.12)^3 \]
\[ 11\,585.12 = P(0.88)^3 \]
\[ 11\,585.12 = P \times 0.681472 \]
\[ P = \frac{11\,585.12}{0.681472} = 17\,000 \]

The original value of the car is $17\,000.

Marking scheme

M1 for \(P \times (1 - 0.12)^3 = 11\,585.12\) or \(P \times 0.88^3 = 11\,585.12\) oe
M1 for \(\frac{11\,585.12}{0.88^3}\) or \(\frac{11\,585.12}{0.681472}\)
A1 for 17000
Question 2 · short-answer
3 marks
The mass, \(m\), of a metal block is \(450\text{ g}\), correct to the nearest \(10\text{ g}\).
The volume, \(V\), of the block is \(52\text{ cm}^3\), correct to the nearest \(1\text{ cm}^3\).

Calculate the upper bound for the density of the metal block in \(\text{g/cm}^3\).
Give your answer correct to 3 decimal places.
Show answer & marking scheme

Worked solution

First find the upper bound of the mass and the lower bound of the volume:
- Upper bound of mass: \(m_{\text{UB}} = 450 + 5 = 455\text{ g}\)
- Lower bound of volume: \(V_{\text{LB}} = 52 - 0.5 = 51.5\text{ cm}^3\)

To maximise density \(D = \frac{m}{V}\):
\[ D_{\text{UB}} = \frac{m_{\text{UB}}}{V_{\text{LB}}} = \frac{455}{51.5} \approx 8.834951... \]

Rounding to 3 decimal places gives \(8.835\text{ g/cm}^3\).

Marking scheme

B1 for 455 or 51.5 seen
M1 for \(\frac{\text{their } 455}{\text{their } 51.5}\) where \(450 < \text{their } 455 \le 455\) and \(51.5 \le \text{their } 51.5 < 52\)
A1 for 8.835 (correct to 3 d.p.)
Question 3 · short-answer
3 marks
\(y\) is inversely proportional to \((x + 1)^2\).
When \(x = 3\), \(y = 5\).

Find the value of \(y\) when \(x = 7\).
Show answer & marking scheme

Worked solution

Since \(y\) is inversely proportional to \((x + 1)^2\):
\[ y = \frac{k}{(x + 1)^2} \]

Substitute \(x = 3\) and \(y = 5\):
\[ 5 = \frac{k}{(3 + 1)^2} = \frac{k}{16} \implies k = 5 \times 16 = 80 \]

Now find \(y\) when \(x = 7\):
\[ y = \frac{80}{(7 + 1)^2} = \frac{80}{64} = 1.25 \]

Marking scheme

M1 for \(y = \frac{k}{(x + 1)^2}\) oe
M1 for substituting \(x = 3\), \(y = 5\) to find \(k = 80\)
A1 for 1.25 or \(\frac{5}{4}\)
Question 4 · short-answer
3 marks
Ethan exchanges £850 into Euros (€) at an exchange rate of £1 = €1.16.
The exchange bureau charges a commission fee of 1.5%, which is deducted from the pounds before the currency is converted.

Calculate the amount of Euros Ethan receives.
Show answer & marking scheme

Worked solution

1. Calculate the commission fee or remaining percentage in pounds:
\[ 850 \times (1 - 0.015) = 850 \times 0.985 = 837.25 \text{ pounds} \]

2. Convert the remaining pounds to Euros at the rate of £1 = €1.16:
\[ 837.25 \times 1.16 = 971.21 \text{ Euros} \]

Marking scheme

M1 for \(850 \times (1 - 0.015)\) or \(850 - 0.015 \times 850\) oe (giving 837.25)
M1 for \(\text{their } 837.25 \times 1.16\)
A1 for 971.21
Question 5 · short-answer
3 marks
A runner completes a distance of \(400\text{ m}\), correct to the nearest metre, in a time of \(52.4\text{ s}\), correct to 1 decimal place.

Calculate the lower bound for the runner's average speed in metres per second.
Give your answer correct to 4 significant figures.
Show answer & marking scheme

Worked solution

Find the lower bound for distance and upper bound for time:
- Distance: \(d_{\text{LB}} = 400 - 0.5 = 399.5\text{ m}\)
- Time: \(t_{\text{UB}} = 52.4 + 0.05 = 52.45\text{ s}\)

To minimise average speed \(s = \frac{d}{t}\):
\[ s_{\text{LB}} = \frac{d_{\text{LB}}}{t_{\text{UB}}} = \frac{399.5}{52.45} \approx 7.61677788... \]

Correct to 4 significant figures, the lower bound is \(7.617\text{ m/s}\).

Marking scheme

B1 for 399.5 or 52.45 seen
M1 for \(\frac{\text{their } 399.5}{\text{their } 52.45}\) where \(399.5 \le \text{their } 399.5 < 400\) and \(52.4 < \text{their } 52.45 \le 52.45\)
A1 for 7.617 (correct to 4 s.f.)
Question 6 · short-answer
3 marks
\(P\) is directly proportional to the cube root of \(w\).
When \(w = 64\), \(P = 18\).

Find the value of \(w\) when \(P = 27\).
Show answer & marking scheme

Worked solution

Since \(P\) is directly proportional to \(\sqrt[3]{w}\):
\[ P = k\sqrt[3]{w} \]

Substitute \(w = 64\) and \(P = 18\):
\[ 18 = k\sqrt[3]{64} = k \times 4 \implies k = \frac{18}{4} = 4.5 \]

Now set \(P = 27\) to solve for \(w\):
\[ 27 = 4.5\sqrt[3]{w} \]
\[ \sqrt[3]{w} = \frac{27}{4.5} = 6 \]
\[ w = 6^3 = 216 \]

Marking scheme

M1 for \(P = k\sqrt[3]{w}\) and substituting \(w = 64, P = 18\) to get \(k = 4.5\) oe
M1 for \(27 = 4.5\sqrt[3]{w}\) leading to \(\sqrt[3]{w} = 6\) or \(w = \left(\frac{27}{4.5}\right)^3\)
A1 for 216
Question 7 · short-answer
3 marks
Maya invests $6500 in a savings account paying compound interest at a rate of 3.2% per year.

Calculate the total interest earned at the end of 4 years.
Give your answer correct to the nearest cent.
Show answer & marking scheme

Worked solution

1. Calculate the total value of the investment after 4 years using the compound interest formula:
\[ A = P(1 + r)^n \]
\[ A = 6500(1 + 0.032)^4 = 6500(1.032)^4 \approx 6500 \times 1.13426702 = 7372.7356... \]

2. Calculate the total interest earned by subtracting the principal:
\[ \text{Interest} = A - P = 7372.7356... - 6500 = 872.7356... \]

Rounding to the nearest cent (2 decimal places) gives $872.74.

Marking scheme

M1 for \(6500 \times (1 + 0.032)^4\) or \(6500 \times 1.032^4\) (giving 7372.74)
M1 for \(\text{their } 7372.74 - 6500\)
A1 for 872.74
Question 8 · Extended Curve Plotting & Intersections
7.5 marks
The table shows some values of \(y = \dfrac{6}{x} + x^2 - 4x\) for \(0.8 \le x \le 5\).

$$
\begin{array}{|c|c|c|c|c|c|c|c|c|c|}
\hline
x & 0.8 & 1 & 1.5 & 2 & 2.5 & 3 & 3.5 & 4 & 5 \\
\hline
y & 4.94 & a & 0.25 & -1 & b & -1 & -0.04 & 1.5 & 6.2 \\
\hline
\end{array}
$$

(a) Work out the value of \(a\) and the value of \(b\).

(b) On a grid, with \(x\)-axis from \(0\) to \(5\) (scale \(2\text{ cm} = 1\text{ unit}\)) and \(y\)-axis from \(-2\) to \(8\) (scale \(2\text{ cm} = 2\text{ units}\)), draw the curve \(y = \dfrac{6}{x} + x^2 - 4x\) for \(0.8 \le x \le 5\).

(c) (i) Use your graph to write down an estimate for the minimum value of \(y\).

(ii) By drawing a suitable straight line on the grid, solve the equation \(\dfrac{6}{x} + x^2 - 5x + 1 = 0\).
Show answer & marking scheme

Worked solution

(a)
For \(x = 1\):
\(a = \dfrac{6}{1} + 1^2 - 4(1) = 6 + 1 - 4 = 3\)

For \(x = 2.5\):
\(b = \dfrac{6}{2.5} + 2.5^2 - 4(2.5) = 2.4 + 6.25 - 10 = -1.35\)

(b)
Plot all 9 points accurately and join with a smooth, continuous single curve.

(c)(i)
From the turning point on the graph, the minimum value of \(y\) occurs at \(x \approx 2.4\) where \(y \approx -1.38\) to \(-1.4\).
Acceptable range: \(-1.45 \le y \le -1.35\).

(c)(ii)
Rearrange the equation to match the graphed function:
\(\dfrac{6}{x} + x^2 - 5x + 1 = 0 \implies \dfrac{6}{x} + x^2 - 4x = x - 1\)
Draw the straight line \(y = x - 1\) on the grid through points such as \((1, 0)\), \((3, 2)\), \((5, 4)\).
Find the \(x\)-coordinates of the intersection points of the line and curve:
\(x \approx 1.2\) (range \(1.15\) to \(1.25\))
\(x = 2.0\)
\(x \approx 4.8\) (range \(4.75\) to \(4.85\))

Marking scheme

(a) [2 marks]
B1 for \(a = 3\)
B1 for \(b = -1.35\)

(b) [2.5 marks]
M1 for at least 6 points plotted correctly
A1 for all 9 points plotted correctly
A0.5 for a smooth curve drawn through all points without discontinuity or flat apex

(c)(i) [1 mark]
B1 for value in range \([-1.45, -1.35]\)

(c)(ii) [2 marks]
M1 for drawing the straight line \(y = x - 1\) with at least two correct points
A1 for all three correct intersection values: \(x \in [1.15, 1.25]\), \(x = 2.0\), \(x \in [4.75, 4.85]\) (A0.5 for two correct)
Question 9 · Extended Curve Plotting & Intersections
7.5 marks
The table shows some values for \(y = x^2 - \dfrac{6}{x} - 1\) for \(0.8 \le x \le 4\).

$$\begin{array}{|c|c|c|c|c|c|c|c|c|}\hline x & 0.8 & 1 & 1.5 & 2 & 2.5 & 3 & 3.5 & 4 \\hline y & -7.86 & -6 & p & 0 & q & 6 & 9.54 & r \\hline\end{array}$$

(a) Work out the values of \(p\), \(q\) and \(r\).
(b) On a grid with \(x\)-axis from \(0\) to \(4\) with a scale of \(2\text{ cm} = 1\text{ unit}\) and \(y\)-axis from \(-8\) to \(14\) with a scale of \(2\text{ cm} = 2\text{ units}\), draw the graph of \(y = x^2 - \dfrac{6}{x} - 1\) for \(0.8 \le x \le 4\).
(c) (i) Use your graph to solve the equation \(x^2 - \dfrac{6}{x} - 1 = 4\).
(ii) By drawing a suitable straight line on your grid, solve the equation \(x^2 - 2x - \dfrac{6}{x} + 2 = 0\).
Show answer & marking scheme

Worked solution

(a) Substitute the given \(x\)-values into \(y = x^2 - \dfrac{6}{x} - 1\):
- For \(x = 1.5\): \(p = (1.5)^2 - \dfrac{6}{1.5} - 1 = 2.25 - 4 - 1 = -2.75\)
- For \(x = 2.5\): \(q = (2.5)^2 - \dfrac{6}{2.5} - 1 = 6.25 - 2.4 - 1 = 2.85\)
- For \(x = 4\): \(r = (4)^2 - \dfrac{6}{4} - 1 = 16 - 1.5 - 1 = 13.5\)

(b) Plot the 8 points \((0.8, -7.86)\), \((1, -6)\), \((1.5, -2.75)\), \((2, 0)\), \((2.5, 2.85)\), \((3, 6)\), \((3.5, 9.54)\), \((4, 13.5)\) and join them with a smooth, continuous curve.

(c) (i) Draw or read across from the horizontal line \(y = 4\) to find the \(x\)-coordinate on the curve: \(x \approx 2.67\) (accept \(2.65\) to \(2.70\)).

(ii) Rearrange \(x^2 - 2x - \dfrac{6}{x} + 2 = 0\) to match the plotted function:
\(x^2 - \dfrac{6}{x} - 1 = 2x - 3\)
Draw the straight line \(y = 2x - 3\) on the grid passing through e.g. \((1, -1)\), \((2, 1)\), \((3, 3)\).
The \(x\)-coordinates of the points of intersection are \(x \approx 1.25\) (accept \(1.20\) to \(1.30\)) and \(x \approx 2.78\) (accept \(2.75\) to \(2.85\)).

Marking scheme

(a) B2 for all 3 values correct (B1 for 2 values correct)
(b) M1 for at least 6 points correctly plotted within 1 mm (half a small square)
A1 for all 8 points correctly plotted
A1 for a smooth, single-strand curve drawn through all points from x = 0.8 to x = 4
(c)(i) B1 for x = 2.65 to 2.70 (or FT from their curve)
(c)(ii) M1 for drawing the line y = 2x - 3 with correct intercept or gradient
A1 for both solutions x = 1.20 to 1.30 and x = 2.75 to 2.85 (or FT their intersection points)
Question 10 · structured
6 marks
A coastguard station is located at point \(P\). Two vessels, \(Q\) and \(R\), are observed in the open sea.
\(Q\) is \(48\text{ km}\) from \(P\) on a bearing of \(062^\circ\).
\(R\) is \(75\text{ km}\) from \(P\) on a bearing of \(145^\circ\).

(a) Calculate the distance between vessel \(Q\) and vessel \(R\). [3]

(b) Calculate the bearing of vessel \(R\) from vessel \(Q\). [3]
Show answer & marking scheme

Worked solution

(a) The angle \(\angle QPR = 145^\circ - 62^\circ = 83^\circ\).
Using the cosine rule in \(\triangle PQR\):
\[ QR^2 = PQ^2 + PR^2 - 2(PQ)(PR)\cos(\angle QPR) \]
\[ QR^2 = 48^2 + 75^2 - 2(48)(75)\cos(83^\circ) \]
\[ QR^2 = 2304 + 5625 - 7200\cos(83^\circ) = 7929 - 877.459 = 7051.541 \]
\[ QR = \sqrt{7051.541} \approx 83.973\text{ km} \approx 84.0\text{ km} \]

(b) Using the sine rule in \(\triangle PQR\) to find \(\angle PQR\):
\[ \frac{\sin(\angle PQR)}{75} = \frac{\sin(83^\circ)}{83.973} \]
\[ \sin(\angle PQR) = \frac{75 \times \sin(83^\circ)}{83.973} \approx 0.8865 \]
\[ \angle PQR = \arcsin(0.8865) \approx 62.44^\circ \]
The back-bearing of \(P\) from \(Q\) is \(062^\circ + 180^\circ = 242^\circ\).
Therefore, the bearing of \(R\) from \(Q\) is:
\[ 242^\circ - 62.44^\circ = 179.56^\circ \approx 180^\circ \text{ or } 179.6^\circ \]

Marking scheme

(a)
M1 for \(\angle QPR = 145^\circ - 62^\circ = 83^\circ\)
M1 for correct implicit cosine rule: \(48^2 + 75^2 - 2(48)(75)\cos(83^\circ)\)
A1 for \(84.0\) or \(83.97\dots\) (accept 84)

(b)
M1 for correct sine rule setup: \(\frac{\sin(\angle PQR)}{75} = \frac{\sin(83^\circ)}{83.97}\) or cosine rule to find \(\angle PQR\)
A1 for \(\angle PQR = 62.4^\circ\) or \(62.44^\circ\)
A1 for bearing \(179.6^\circ\) or \(180^\circ\) (accept \(179.5^\circ\) to \(180^\circ\))
Question 11 · structured
6 marks
A vertical communication mast \(VT\) of height \(h\) metres stands on horizontal ground, with base \(T\).
Point \(A\) on the ground is due South of \(T\), and point \(B\) on the ground is due East of \(T\).
The angle of elevation of the top of the mast \(V\) from \(A\) is \(28^\circ\).
The angle of elevation of \(V\) from \(B\) is \(35^\circ\).
The straight-line distance between \(A\) and \(B\) is \(85\text{ m}\).

(a) Show that \(h = 36.0\text{ m}\), correct to 3 significant figures. [3]

(b) Point \(M\) is the midpoint of the line segment \(AB\).
Calculate the angle of elevation of \(V\) from \(M\). [3]
Show answer & marking scheme

Worked solution

(a) In the right-angled triangle \(VTA\):
\[ TA = \frac{h}{\tan 28^\circ} \]
In the right-angled triangle \(VTB\):
\[ TB = \frac{h}{\tan 35^\circ} \]
Since \(A\) is due South and \(B\) is due East of \(T\), \(\angle ATB = 90^\circ\).
Using Pythagoras' theorem in \(\triangle ATB\):
\[ TA^2 + TB^2 = AB^2 \]
\[ \left(\frac{h}{\tan 28^\circ}\right)^2 + \left(\frac{h}{\tan 35^\circ}\right)^2 = 85^2 \]
\[ h^2 \left( \frac{1}{\tan^2 28^\circ} + \frac{1}{\tan^2 35^\circ} \right) = 7225 \]
\[ h^2 (3.53713 + 2.03961) = 7225 \implies h^2 (5.57674) = 7225 \]
\[ h^2 = \frac{7225}{5.57674} \approx 1295.56 \implies h \approx 35.994\text{ m} = 36.0\text{ m} \text{ (3 s.f.)} \]

(b) Since \(\angle ATB = 90^\circ\) and \(M\) is the midpoint of the hypotenuse \(AB\):
\[ TM = \frac{1}{2} AB = \frac{85}{2} = 42.5\text{ m} \]
In the right-angled triangle \(VTM\):
\[ \tan(\angle VMT) = \frac{VT}{TM} = \frac{35.994}{42.5} \approx 0.8469 \]
\[ \angle VMT = \arctan(0.8469) \approx 40.26^\circ \approx 40.3^\circ \]

Marking scheme

(a)
M1 for expressing \(TA = \frac{h}{\tan 28^\circ}\) and \(TB = \frac{h}{\tan 35^\circ}\)
M1 for substituting into Pythagoras: \(\left(\frac{h}{\tan 28^\circ}\right)^2 + \left(\frac{h}{\tan 35^\circ}\right)^2 = 85^2\)
A1 for fully correct calculation leading to \(h = 35.99\dots\) and rounding to \(36.0\)

(b)
M1 for finding \(TM = 42.5\) (or using coordinates / Pythagoras)
M1 for \(\tan(\theta) = \frac{35.994}{42.5}\) or \(\frac{36.0}{42.5}\)
A1 for \(40.3^\circ\) or \(40.26^\circ\dots\)
Question 12 · structured
6 marks
A nature reserve boundary forms a quadrilateral \(ABCD\) on flat ground.
\(AB = 65\text{ m}\), \(BC = 82\text{ m}\), and \(\angle ABC = 112^\circ\).
In triangle \(ACD\), \(\angle CAD = 48^\circ\) and \(\angle ACD = 39^\circ\).

(a) Calculate the length of the diagonal path \(AC\). [3]

(b) Calculate the shortest distance from point \(B\) to the path \(AC\). [3]
Show answer & marking scheme

Worked solution

(a) In \(\triangle ABC\), use the cosine rule:
\[ AC^2 = AB^2 + BC^2 - 2(AB)(BC)\cos(\angle ABC) \]
\[ AC^2 = 65^2 + 82^2 - 2(65)(82)\cos(112^\circ) \]
\[ AC^2 = 4225 + 6724 - 10660(-0.3746) = 10949 + 3993.31 = 14942.31 \]
\[ AC = \sqrt{14942.31} \approx 122.24\text{ m} \approx 122\text{ m} \]

(b) The area of \(\triangle ABC\) is:
\[ \text{Area} = \frac{1}{2} \times 65 \times 82 \times \sin(112^\circ) \approx 2470.95\text{ m}^2 \]
The shortest distance \(d\) from \(B\) to \(AC\) is the perpendicular height:
\[ \text{Area} = \frac{1}{2} \times AC \times d \]
\[ 2470.95 = \frac{1}{2} \times 122.24 \times d \]
\[ d = \frac{2 \times 2470.95}{122.24} \approx 40.43\text{ m} \approx 40.4\text{ m} \]

Marking scheme

(a)
M1 for implicit cosine rule: \(65^2 + 82^2 - 2(65)(82)\cos(112^\circ)\)
A1 for \(14942\dots\)
A1 for \(122\) or \(122.2\dots\)

(b)
M1 for area of \(\triangle ABC = \frac{1}{2} \times 65 \times 82 \times \sin(112^\circ)\) or finding an interior angle
M1 for equating area to \(\frac{1}{2} \times AC \times d\) or using \(d = 65\sin(\angle BAC)\)
A1 for \(40.4\) or \(40.42\dots\) to \(40.43\dots\)
Question 13 · structured
6 marks
A storage facility is in the shape of a cuboid \(ABCD-EFGH\) with a horizontal rectangular base \(ABCD\).
\(AB = 14\text{ m}\), \(BC = 9\text{ m}\), and the vertical height \(AE = 6\text{ m}\).
Point \(M\) is the centre of the top rectangular face \(EFGH\).

(a) Calculate the length of the straight beam connecting vertex \(A\) to \(M\). [3]

(b) Calculate the angle that the beam \(AM\) makes with the horizontal base \(ABCD\). [3]
Show answer & marking scheme

Worked solution

(a) Let \(A\) be the origin \((0, 0, 0)\).
Then \(B = (14, 0, 0)\), \(D = (0, 9, 0)\), and \(E = (0, 0, 6)\).
The centre \(M\) of the top face \(EFGH\) has coordinates \((7, 4.5, 6)\).
The distance \(AM\) is:
\[ AM = \sqrt{7^2 + 4.5^2 + 6^2} = \sqrt{49 + 20.25 + 36} = \sqrt{105.25} \approx 10.259\text{ m} \approx 10.3\text{ m} \]

(b) Let \(M'\) be the projection of \(M\) onto the base \(ABCD\), so \(M' = (7, 4.5, 0)\).
The length of \(AM'\) on the base is:
\[ AM' = \sqrt{7^2 + 4.5^2} = \sqrt{69.25} \approx 8.322\text{ m} \]
The angle \(\theta\) between \(AM\) and the horizontal base is \(\angle MAM'\) in right-angled \(\triangle AMM'\):
\[ \tan\theta = \frac{MM'}{AM'} = \frac{6}{\sqrt{69.25}} \approx 0.7210 \]
\[ \theta = \arctan(0.7210) \approx 35.79^\circ \approx 35.8^\circ \]

Marking scheme

(a)
M1 for finding half-lengths \(7\) and \(4.5\) (or diagonal of face \(\sqrt{14^2 + 9^2}\))
M1 for \(7^2 + 4.5^2 + 6^2\) or \((\frac{1}{2}\sqrt{277})^2 + 6^2\)
A1 for \(10.3\) or \(10.25\dots\) to \(10.26\dots\)

(b)
M1 for identifying the correct right-angled triangle with vertical height \(6\) and base distance \(\sqrt{69.25}\) (or using \(\sin\theta = \frac{6}{AM}\))
M1 for \(\tan\theta = \frac{6}{\sqrt{69.25}}\) or \(\sin\theta = \frac{6}{\sqrt{105.25}}\) or \(\cos\theta = \frac{\sqrt{69.25}}{\sqrt{105.25}}\)
A1 for \(35.8^\circ\) or \(35.79^\circ\dots\)
Question 14 · structured
6 marks
Three survey beacons \(X\), \(Y\), and \(Z\) are positioned on horizontal ground.
\(Y\) is \(120\text{ m}\) from \(X\) on a bearing of \(078^\circ\).
\(Z\) is on a bearing of \(134^\circ\) from \(X\) and on a bearing of \(218^\circ\) from \(Y\).

(a) Show that \(\angle YXZ = 56^\circ\) and find \(\angle XYZ\). [2]

(b) Calculate the distance \(XZ\). [2]

(c) Calculate the area of triangle \(XYZ\). [2]
Show answer & marking scheme

Worked solution

(a) \(\angle YXZ = 134^\circ - 078^\circ = 56^\circ\).
The back-bearing of \(X\) from \(Y\) is \(078^\circ + 180^\circ = 258^\circ\).
The bearing of \(Z\) from \(Y\) is \(218^\circ\).
Therefore, \(\angle XYZ = 258^\circ - 218^\circ = 40^\circ\).

(b) In \(\triangle XYZ\), the third angle is:
\[ \angle XZY = 180^\circ - (56^\circ + 40^\circ) = 84^\circ \]
Using the sine rule:
\[ \frac{XZ}{\sin(\angle XYZ)} = \frac{XY}{\sin(\angle XZY)} \]
\[ \frac{XZ}{\sin(40^\circ)} = \frac{120}{\sin(84^\circ)} \]
\[ XZ = \frac{120 \times \sin(40^\circ)}{\sin(84^\circ)} \approx \frac{77.1345}{0.9945} \approx 77.56\text{ m} \approx 77.6\text{ m} \]

(c) The area of \(\triangle XYZ\) is:
\[ \text{Area} = \frac{1}{2} \times XY \times XZ \times \sin(\angle YXZ) \]
\[ \text{Area} = \frac{1}{2} \times 120 \times 77.56 \times \sin(56^\circ) \approx 60 \times 77.56 \times 0.8290 \approx 3858\text{ m}^2 \approx 3860\text{ m}^2 \]

Marking scheme

(a)
B1 for \(\angle YXZ = 134^\circ - 78^\circ = 56^\circ\) correctly shown
B1 for \(\angle XYZ = 40^\circ\)

(b)
M1 for correct sine rule setup: \(\frac{XZ}{\sin 40^\circ} = \frac{120}{\sin 84^\circ}\)
A1 for \(77.6\) or \(77.55\dots\) to \(77.56\dots\)

(c)
M1 for area formula: \(\frac{1}{2} \times 120 \times (\text{their } XZ) \times \sin(56^\circ)\)
A1 for \(3860\) or \(3858\dots\)
Question 15 · structured
6 marks
A right prism has a horizontal rectangular base \(PQRS\) with \(PQ = 18\text{ cm}\) and \(QR = 25\text{ cm}\).
The vertical triangular cross-section is \(PQT\), where \(\angle TPQ = 90^\circ\) and \(PT = 11\text{ cm}\).
The opposite triangular face is \(SRU\), with vertical edge \(SU = 11\text{ cm}\).

(a) Calculate the length of the diagonal \(TR\). [3]

(b) Calculate the angle that the diagonal \(TR\) makes with the horizontal base \(PQRS\). [2]

(c) Point \(K\) lies on the vertical edge \(SU\) such that \(SK = 4\text{ cm}\).
Calculate the angle of elevation of \(T\) from \(K\). [1]
Show answer & marking scheme

Worked solution

(a) Using coordinates with \(P = (0, 0, 0)\):
\(Q = (18, 0, 0)\), \(R = (18, 25, 0)\), \(S = (0, 25, 0)\), \(T = (0, 0, 11)\).
The distance \(TR\) is:
\[ TR = \sqrt{(18 - 0)^2 + (25 - 0)^2 + (0 - 11)^2} = \sqrt{18^2 + 25^2 + 11^2} \]
\[ TR = \sqrt{324 + 625 + 121} = \sqrt{1070} \approx 32.71\text{ cm} \approx 32.7\text{ cm} \]

(b) The projection of \(T\) onto the base \(PQRS\) is \(P\).
The horizontal distance \(PR\) is:
\[ PR = \sqrt{18^2 + 25^2} = \sqrt{949} \approx 30.81\text{ cm} \]
In right-angled \(\triangle TPR\):
\[ \tan(\angle TRP) = \frac{PT}{PR} = \frac{11}{\sqrt{949}} \approx 0.3571 \]
\[ \angle TRP = \arctan(0.3571) \approx 19.65^\circ \approx 19.7^\circ \]

(c) The coordinates of \(K\) are \((0, 25, 4)\) and \(T = (0, 0, 11)\).
The horizontal distance between \(K\) and \(T\) is \(25\text{ cm}\).
The vertical difference in height is \(11 - 4 = 7\text{ cm}\).
The angle of elevation \(\phi\) is:
\[ \tan\phi = \frac{7}{25} = 0.28 \]
\[ \phi = \arctan(0.28) \approx 15.64^\circ \approx 15.6^\circ \]

Marking scheme

(a)
M1 for \(PR = \sqrt{18^2 + 25^2} = \sqrt{949}\) (or \(30.8\dots\))
M1 for \(TR = \sqrt{949 + 11^2} = \sqrt{1070}\)
A1 for \(32.7\) or \(32.71\dots\)

(b)
M1 for \(\tan\theta = \frac{11}{\sqrt{949}}\) or \(\sin\theta = \frac{11}{\sqrt{1070}}\) or \(\cos\theta = \frac{\sqrt{949}}{\sqrt{1070}}\)
A1 for \(19.7^\circ\) or \(19.65^\circ\dots\)

(c)
B1 for \(\tan\phi = \frac{7}{25} \implies \phi = 15.6^\circ\) or \(15.64^\circ\dots\)
Question 16 · short_answer
3 marks
The table shows information about the masses, \(m\) grams, of 120 apples.

\[ \begin{array}{|c|c|} \hline \text{Mass } (m\text{ g}) & \text{Frequency} \\ \hline 100 < m \le 120 & 18 \\ 120 < m \le 130 & 33 \\ 130 < m \le 145 & 45 \\ 145 < m \le 170 & 24 \\ \hline \end{array} \]

In a histogram representing this data, the bar for the class \(120 < m \le 130\) has a width of \(2\text{ cm}\) and a height of \(6.6\text{ cm}\).

Calculate the width and the height of the bar representing the class \(145 < m \le 170\).
Show answer & marking scheme

Worked solution

For the class \(120 < m \le 130\):
- Class width = \(130 - 120 = 10\)
- Frequency density \(= \frac{33}{10} = 3.3\)
- Width on histogram \(= 2\text{ cm} \implies 1\text{ unit on } m\text{-axis} = \frac{2}{10} = 0.2\text{ cm}\)
- Height on histogram \(= 6.6\text{ cm} \implies 1\text{ unit of frequency density} = \frac{6.6}{3.3} = 2\text{ cm}\)

For the class \(145 < m \le 170\):
- Class width \(= 170 - 145 = 25\)
- Width of bar \(= 25 \times 0.2 = 5\text{ cm}\)
- Frequency density \(= \frac{24}{25} = 0.96\)
- Height of bar \(= 0.96 \times 2 = 1.92\text{ cm}\)

Marking scheme

B1: for width \(= 5\text{ cm}\)
M1: for finding frequency density \(= \frac{24}{25} = 0.96\) or for scale factor \(\frac{6.6}{3.3} = 2\) (or equivalent ratio)
A1: for height \(= 1.92\text{ cm}\)
Question 17 · short_answer
3 marks
The table shows information about the distance, \(d\text{ km}\), travelled to work by 80 employees of a company.

\[ \begin{array}{|c|c|} \hline \text{Distance } (d\text{ km}) & \text{Frequency} \\ \hline 0 < d \le 5 & 16 \\ 5 < d \le 15 & 28 \\ 15 < d \le 25 & 22 \\ 25 < d \le 40 & 14 \\ \hline \end{array} \]

Calculate an estimate of the mean distance travelled.
Show answer & marking scheme

Worked solution

Find midpoints of each interval:
- \(0 < d \le 5\): midpoint \(= 2.5\)
- \(5 < d \le 15\): midpoint \(= 10\)
- \(15 < d \le 25\): midpoint \(= 20\)
- \(25 < d \le 40\): midpoint \(= 32.5\)

Calculate \(\sum f x\):
\[ \sum f x = (16 \times 2.5) + (28 \times 10) + (22 \times 20) + (14 \times 32.5) \]
\[ \sum f x = 40 + 280 + 440 + 455 = 1215 \]

Calculate the estimated mean:
\[ \text{Mean} = \frac{1215}{80} = 15.1875 \]
Rounding to 3 significant figures gives \(15.2\text{ km}\).

Marking scheme

M1: for identifying correct midpoints \(2.5, 10, 20, 32.5\) (at least 3 correct)
M1: (dep on previous M1) for \(\sum f x\) calculation \(= 16(2.5) + 28(10) + 22(20) + 14(32.5) (= 1215)\) divided by 80
A1: for \(15.2\) or \(15.1875\) or \(15.19\)
Question 18 · short_answer
3 marks
A histogram is drawn to represent the ages, \(x\) years, of 120 visitors to an exhibition.

The class intervals and corresponding frequency densities are given below:

\[ \begin{array}{|c|c|} \hline \text{Age } (x\text{ years}) & \text{Frequency Density} \\ \hline 0 < x \le 20 & 1.2 \\ 20 < x \le 30 & 3.6 \\ 30 < x \le 50 & 2.2 \\ 50 < x \le 70 & 0.8 \\ \hline \end{array} \]

Estimate the number of visitors who are aged between 25 and 45 years.
Show answer & marking scheme

Worked solution

To estimate the number of visitors aged between 25 and 45 years:

1. From \(20 < x \le 30\), the interval from \(x = 25\) to \(x = 30\) has width \(30 - 25 = 5\).
\[ \text{Frequency} = 5 \times 3.6 = 18 \]

2. From \(30 < x \le 50\), the interval from \(x = 30\) to \(x = 45\) has width \(45 - 30 = 15\).
\[ \text{Frequency} = 15 \times 2.2 = 33 \]

3. Total estimated visitors:
\[ 18 + 33 = 51 \]

Marking scheme

M1: for calculating \(5 \times 3.6 (= 18)\)
M1: for calculating \(15 \times 2.2 (= 33)\)
A1: for \(51\)
Question 19 · short_answer
4 marks
The table gives information about the time, \(t\) minutes, taken by 200 customers to complete an online order.

\[ \begin{array}{|c|c|} \hline \text{Time } (t\text{ minutes}) & \text{Frequency} \\ \hline 0 < t \le 4 & a \\ 4 < t \le 8 & 56 \\ 8 < t \le 12 & 64 \\ 12 < t \le 20 & b \\ 20 < t \le 30 & 20 \\ \hline \end{array} \]

In a histogram representing this data, the height of the bar for the class \(4 < t \le 8\) is \(7\text{ cm}\) and the height of the bar for the class \(12 < t \le 20\) is \(2.5\text{ cm}\).

Work out the value of \(a\) and the value of \(b\).
Show answer & marking scheme

Worked solution

For the class \(4 < t \le 8\):
- Class width \(= 8 - 4 = 4\)
- Frequency density \(= \frac{56}{4} = 14\)
- Since height \(= 7\text{ cm}\), the scale factor is \(\frac{7}{14} = 0.5\text{ cm}\) per unit of frequency density (or \(\text{frequency density} = 2 \times \text{height}\)).

For the class \(12 < t \le 20\):
- Height \(= 2.5\text{ cm} \implies \text{frequency density} = 2.5 \times 2 = 5\)
- Class width \(= 20 - 12 = 8\)
- \(b = 5 \times 8 = 40\)

The total number of customers is 200:
\[ a + 56 + 64 + b + 20 = 200 \]
\[ a + 56 + 64 + 40 + 20 = 200 \]
\[ a + 180 = 200 \implies a = 20 \]

Marking scheme

M1: for frequency density of \(4 < t \le 8\) as \(\frac{56}{4} = 14\) or relation \(1\text{ cm} = 2\text{ units of FD}\)
M1: for \(b = 2.5 \times 2 \times 8\) or equivalent method
A1: for \(b = 40\)
A1: for \(a = 20\)
Question 20 · short_answer
5 marks
A cyclist travels an outward journey of \(45\text{ km}\) at an average speed of \(x\text{ km/h}\).
On the return journey along the same route, their average speed is \((x - 3)\text{ km/h}\).
The return journey takes \(45\text{ minutes}\) longer than the outward journey.

(a) Write down an expression, in terms of \(x\), for the time taken, in hours, for:
(i) the outward journey, [1]
(ii) the return journey. [1]

(b) Write down an equation in \(x\) and show that it simplifies to \(x^2 - 3x - 180 = 0\). [2]

(c) Solve the equation \(x^2 - 3x - 180 = 0\) to find the average speed of the cyclist on the outward journey. [1]
Show answer & marking scheme

Worked solution

(a)(i) \(\text{Time} = \frac{\text{Distance}}{\text{Speed}} = \frac{45}{x}\text{ hours}\).

(a)(ii) \(\text{Time} = \frac{45}{x - 3}\text{ hours}\).

(b) \(45\text{ minutes} = \frac{45}{60} = \frac{3}{4}\text{ hours}\).

Setting up the difference in time:
\(\frac{45}{x - 3} - \frac{45}{x} = \frac{3}{4}\)

Combine the fractions over a common denominator:
\(\frac{45x - 45(x - 3)}{x(x - 3)} = \frac{3}{4}\)
\(\frac{45x - 45x + 135}{x(x - 3)} = \frac{3}{4}\)
\(\frac{135}{x^2 - 3x} = \frac{3}{4}\)

Cross-multiply:
\(3(x^2 - 3x) = 4 \times 135\)
\(3x^2 - 9x = 540\)
\(3x^2 - 9x - 540 = 0\)

Divide the entire equation by 3:
\(x^2 - 3x - 180 = 0\).

(c) Factorising the quadratic equation:
\((x - 15)(x + 12) = 0\)
\(x = 15\) or \(x = -12\)

Since speed must be positive, \(x = 15\text{ km/h}\).

Marking scheme

(a)(i) B1: for \(\frac{45}{x}\)
(a)(ii) B1: for \(\frac{45}{x - 3}\)
(b) M1: for correct algebraic expression for time difference set equal to \(\frac{3}{4}\) or \(0.75\), e.g. \(\frac{45}{x-3} - \frac{45}{x} = \frac{3}{4}\)
A1: for correct expansion and clear steps shown reaching \(x^2 - 3x - 180 = 0\) with no steps omitted
(c) B1: for \(15\) (ignore \(-12\) if seen, must select positive value)
Question 21 · short_answer
5 marks
Solve the equation
\[\frac{4}{2x - 1} - \frac{3}{x + 2} = 1\]
Show all your working and give your answers correct to 2 decimal places.
Show answer & marking scheme

Worked solution

Multiply all terms by \((2x - 1)(x + 2)\) to eliminate denominators:
\(4(x + 2) - 3(2x - 1) = 1(2x - 1)(x + 2)\)

Expand both sides:
\(4x + 8 - 6x + 3 = 2x^2 + 4x - x - 2\)
\(-2x + 11 = 2x^2 + 3x - 2\)

Rearrange into standard quadratic form \(ax^2 + bx + c = 0\):
\(2x^2 + 3x + 2x - 2 - 11 = 0\)
\(2x^2 + 5x - 13 = 0\)

Apply the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\):
\(a = 2, b = 5, c = -13\)
\(x = \frac{-5 \pm \sqrt{5^2 - 4(2)(-13)}}{2(2)}\)
\(x = \frac{-5 \pm \sqrt{25 + 104}}{4}\)
\(x = \frac{-5 \pm \sqrt{129}}{4}\)

\(x = \frac{-5 + 11.3578...}{4} = 1.589... \approx 1.59\)
\(x = \frac{-5 - 11.3578...}{4} = -4.089... \approx -4.09\)

Marking scheme

M1: for attempting common denominator or multiplying by \((2x - 1)(x + 2)\), e.g. \(4(x + 2) - 3(2x - 1)\)
M1: for expanding brackets correctly on both sides, reaching \(-2x + 11 = 2x^2 + 3x - 2\) or equivalent
A1: for correct 3-term quadratic equation in standard form: \(2x^2 + 5x - 13 = 0\)
M1: for correct substitution into quadratic formula \(\frac{-5 \pm \sqrt{5^2 - 4(2)(-13)}}{2(2)}\) or \(\frac{-5 \pm \sqrt{129}}{4}\) (FT their 3-term quadratic)
A1: for both \(1.59\) and \(-4.09\) correct to 2 decimal places
Question 22 · short_answer
5 marks
A rectangular lawn has a width of \(w\text{ metres}\) and a length of \((w + 3)\text{ metres}\).
A concrete path of uniform width \(1.5\text{ metres}\) is laid completely around the outside of the lawn.
The total area of the lawn and the path combined is \(70\text{ m}^2\).

(a) Show that \(w^2 + 9w - 52 = 0\). [3]

(b) Factorise \(w^2 + 9w - 52\). [1]

(c) Find the width of the lawn. [1]
Show answer & marking scheme

Worked solution

(a) The total width including the path is:
\(w + 2(1.5) = w + 3\text{ m}\).

The total length including the path is:
\((w + 3) + 2(1.5) = w + 3 + 3 = w + 6\text{ m}\).

The total combined area is:
\(\text{Area} = (w + 3)(w + 6)\)

Expanding the brackets:
\((w + 3)(w + 6) = w^2 + 6w + 3w + 18 = w^2 + 9w + 18\)

Given that the total area is \(70\text{ m}^2\):
\(w^2 + 9w + 18 = 70\)
\(w^2 + 9w + 18 - 70 = 0\)
\(w^2 + 9w - 52 = 0\).

(b) Finding factors of \(-52\) that sum to \(+9\):
\(13 \times (-4) = -52\) and \(13 + (-4) = 9\).
Thus, \(w^2 + 9w - 52 = (w + 13)(w - 4)\).

(c) Setting \((w + 13)(w - 4) = 0\) gives \(w = -13\) or \(w = 4\).
Since a physical width cannot be negative, the width of the lawn is \(4\text{ m}\).

Marking scheme

(a) M1: for identifying outer dimensions as \(w + 3\) and \(w + 6\)
M1: for setting up area equation \((w + 3)(w + 6) = 70\)
A1: for expanding brackets correctly to \(w^2 + 9w + 18 = 70\) and concluding with \(w^2 + 9w - 52 = 0\) with all steps clearly shown
(b) B1: for \((w + 13)(w - 4)\)
(c) B1: for \(4\) (must reject \(-13\))

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