Topic – C4.5
Write down the letter of the shape that is congruent to the shaded shape.
▶️ Answer/Explanation
Ans: D
Congruent shapes are identical in shape and size. The shaded shape matches exactly with shape D when rotated.
Topic – C1.1
Write down:
(a) all the factors of 32
(b) the reciprocal of \(\frac{1}{8}\)
(c) the value of the 7 in the number 473 285
▶️ Answer/Explanation
(a) Ans: 1, 2, 4, 8, 16, 32
(b) Ans: 8 (Reciprocal means flipping the fraction)
(c) Ans: 70,000 (The 7 is in the ten-thousands place)
Topic – C4.5
Draw the lines of symmetry on this rhombus.
▶️ Answer/Explanation
Ans: A rhombus has two lines of symmetry – one vertical and one horizontal diagonal.
Draw one line connecting opposite vertices, and another line connecting the other pair of opposite vertices.
Topic – C1.3
From the list, write down:
(a) a cube number
(b) a prime number
▶️ Answer/Explanation
(a) Ans: 64 (4×4×4)
(b) Ans: 61 (Only divisible by 1 and itself)
Note: 63, 66, 68, 69 are all composite numbers.
Topic – C1.15
Tara goes on a journey by train.
The train leaves at 0648.
The journey takes 12 hours and 35 minutes.
Find the time when Tara arrives.
▶️ Answer/Explanation
Ans: 19:23 or 7:23 pm
Start at 06:48, add 12 hours to reach 18:48 (6:48 pm).
Then add 35 minutes: 18:48 + 35 minutes = 19:23.
Topic – C9.3
Jamie records the masses of two samples of oranges, type A and type B. The stem-and-leaf diagram shows the mass, in grams, of each of 30 oranges of type A.
(a) Complete the table to show the range for type A oranges.
(b) Use the information in the table to write down two comments comparing the masses of type A and type B oranges.
▶️ Answer/Explanation
(a) 42 (calculated from stem-and-leaf diagram)
(b) 1. Type A oranges are lighter on average
2. Type A masses are more varied/less consistent
For (a), subtract smallest mass (176g) from largest (218g). For (b), compare means and ranges.
Topic – C4.2
In triangle LMN, LN = 7.5 cm and MN = 8 cm.
(a) Using a ruler and compasses only, construct triangle LMN. Leave in your construction arcs.
The line LM has been drawn for you.
(b) Write down the mathematical name for this triangle.
▶️ Answer/Explanation
(a) Construction with arcs
(b) Scalene
For (a), draw arcs from L (radius 8cm) and M (radius 7.5cm) to find N. For (b), all sides are different lengths.
Topic – C5.4
The surface area of a cube is 73.5 cm². Find the length of one side of the cube.
▶️ Answer/Explanation
3.5 cm
Surface area = 6 × side² → 73.5 ÷ 6 = 12.25 → √12.25 = 3.5 cm.
Topic – C4.6
The diagram shows an equilateral triangle. Find the value of x.
▶️ Answer/Explanation
150
External angle = 360° – internal angle (60° for equilateral) → x = 360 – 60 – 60 – 60 = 150°.
Topic – C7.1
Given vectors: a = \(\begin{pmatrix}4\\9\end{pmatrix}\), b = \(\begin{pmatrix}-6\\1\end{pmatrix}\), c = \(\begin{pmatrix}13\\-2\end{pmatrix}\)
(a) Work out a + b
(b) Work out 3c
▶️ Answer/Explanation
(a) \(\begin{pmatrix}-2\\10\end{pmatrix}\)
(b) \(\begin{pmatrix}39\\-6\end{pmatrix}\)
For (a), add corresponding components. For (b), multiply each component by 3.
Topic – C2.2
Factorise completely.
$15v² – 3v$
▶️ Answer/Explanation
Ans: $3v(5v – 1)$
1. Identify common factor: both terms have 3 and v
2. Factor out 3v: $3v(5v) – 3v(1)$
3. Write final factorised form: $3v(5v – 1)$
Topic – C8.1
Rama asks a group of students how they travel to school. The table shows the probability of how a student, chosen at random, travels to school.
(a) Complete the table.
(b) There are 1800 students at the school. Find the expected number of students that walk to school.
▶️ Answer/Explanation
Ans:
(a) Other probability = 0.11 (1 – 0.4 – 0.32 – 0.17)
(b) Expected walkers = 1800 × 0.32 = 576
1. For (a), subtract given probabilities from 1
2. For (b), multiply total students by walk probability
Topic – C1.4
Without using a calculator, work out $1 \frac{5}{6} ÷ \frac{11}{15}$.
Give your answer as a mixed number in its simplest form.
▶️ Answer/Explanation
Ans: $2 \frac{1}{2}$
1. Convert mixed number to improper fraction: $\frac{11}{6}$
2. Change division to multiplication by reciprocal: $\frac{11}{6} × \frac{15}{11}$
3. Simplify: $\frac{15}{6} = \frac{5}{2} = 2 \frac{1}{2}$
Topic – C4.1
The diagram shows triangle ABC. M is the midpoint of AC.
Triangle ABC is rotated 180° about centre M.
The image and the original triangle together form a quadrilateral ABCD.
(a) Write down the name of quadrilateral ABCD formed.
(b) Find angle BAD.
▶️ Answer/Explanation
Ans:
(a) Parallelogram
(b) 68°
1. 180° rotation creates parallelogram
2. Angle BAD = 180° – 112° = 68° (angles on straight line)
Topic – C1.16
Shubhu invests $750 in a savings account for 5 years.
The account pays simple interest at 1.8% per year.
Calculate the total interest earned.
▶️ Answer/Explanation
Ans: $67.50
1. Calculate annual interest: $750 × 1.8% = $13.50
2. Multiply by 5 years: $13.50 × 5 = $67.50
Or in one step: $750 × 1.8% × 5
Topic – C2.5
Solve the equation.
5x + 7 = 9x – 3
▶️ Answer/Explanation
Ans: 2.5
5x + 7 = 9x – 3
7 + 3 = 9x – 5x
10 = 4x
x = 2.5
Topic – C3.5
(a) Find the equation of line L in the form y = mx + c
(b) On the grid, draw a line that is perpendicular to line L
▶️ Answer/Explanation
Ans:
(a) y = (1/3)x + 1 (from the graph, slope is 1/3 and y-intercept is 1)
(b) Any line with slope -3 (negative reciprocal of 1/3) would be perpendicular
Topic – C2.1
A bar of chocolate costs $3 and a bag of sweets costs $5. Write down an expression for the total cost, in dollars, of x bars of chocolate and y bags of sweets.
▶️ Answer/Explanation
Ans: 3x + 5y
Cost of x chocolate bars = 3 × x = 3x
Cost of y sweet bags = 5 × y = 5y
Total cost = 3x + 5y
Topic – C8.1
(a) A bag contains these cards.
One of these cards is picked at random. Find the probability that the number on the card is greater than 3.
(b) A box contains 3 blue and 7 red cards. Kim picks one card at random, notes its colour and then replaces it in the box. She then picks another card at random.
(i) Complete the tree diagram
(ii) Work out the probability that both of the cards Kim picks are blue.
▶️ Answer/Explanation
Ans:
(a) 4/7 (Numbers >3: 7,9,4,5 out of 7 total cards)
(b)(i) Tree diagram should show:
First branch: Blue (3/10) → Second branches: Blue (3/10) and Red (7/10)
First branch: Red (7/10) → Second branches: Blue (3/10) and Red (7/10)
(b)(ii) 9/100 (3/10 × 3/10 = 9/100)
Topic – C5.3
The diagram shows a sector of a circle with radius r cm and sector angle 72°.
The arc length is 9.35 cm.
Calculate the value of r.
▶️ Answer/Explanation
Ans: 7.44
Arc length = (θ/360) × 2πr
9.35 = (72/360) × 2 × 3.142 × r
9.35 = 0.2 × 6.284 × r
r = 9.35 ÷ 1.2568 ≈ 7.44
Topic – C1.2
ξ = {2, 4, 8, 9, 10, 12}
Q = {square numbers}
R = {multiples of 4}
(a) Use this information to complete the Venn diagram.
(b) Write down n(Q ∩ R).
▶️ Answer/Explanation
Ans:
(a) Venn diagram should show: 4, 8 in Q∩R; 9 in Q only; 12 in R only; 2,10 outside both circles
(b) 1 (only 4 is both a square number and multiple of 4 in the given set)
Square numbers in set: 4, 9
Multiples of 4 in set: 4, 8, 12
Intersection Q∩R contains only 4
Topic – C1.1
Find the highest common factor (HCF) of 48 and 80.
▶️ Answer/Explanation
Ans: 16
Prime factors of 48: 2 × 2 × 2 × 2 × 3
Prime factors of 80: 2 × 2 × 2 × 2 × 5
Common prime factors: 2 × 2 × 2 × 2 = 16
Therefore, HCF is 16
Topic – C2.5
Solve the simultaneous equations. You must show all your working.
3x + 5y = 23
6x – 4y = 11
▶️ Answer/Explanation
Ans: x = 3.5, y = 2.5
Multiply first equation by 2: 6x + 10y = 46
Subtract second equation: (6x+10y)-(6x-4y)=46-11 → 14y=35 → y=2.5
Substitute y=2.5 into first equation: 3x+12.5=23 → 3x=10.5 → x=3.5
Check in second equation: 6(3.5)-4(2.5)=21-10=11 ✓