Topic – E1.1
From the list of numbers, write down
(a) a cube number
(b) a prime number
▶️ Answer/Explanation
(a) Ans: 64 (since 4³ = 64)
(b) Ans: 61 or 67 (both are prime numbers)
For part (a), we identify 64 as it’s 4 cubed.
For part (b), we check divisibility: 61 and 67 have no divisors other than 1 and themselves.
Topic – E1.15
A train journey starts at 23:30 and finishes at 07:15 the next day.
Find the time taken for this journey.
▶️ Answer/Explanation
Ans: 7 hours 45 minutes
From 23:30 to 00:30 is 1 hour
From 00:30 to 07:30 is 7 hours
07:30 to 07:15 is -15 minutes
Total = 7 hours + 45 minutes = 7h 45m
Topic – E2.2
Simplify: 3p – t – p – 4t
▶️ Answer/Explanation
Ans: 2p – 5t
Combine like terms:
3p – p = 2p
-t – 4t = -5t
Final simplified form: 2p – 5t
Topic – E4.3
The scale drawing shows the positions of town K and town L.
The scale is 1 cm represents 10 km.
(a) Find the actual distance between town K and town L.
(b) Measure the bearing of town L from town K.
▶️ Answer/Explanation
(a) Ans: 85 km
From the diagram, distance is 8.5 cm
Actual distance = 8.5 × 10 = 85 km
(b) Ans: 065°
Using a protractor, measure the angle from north line clockwise to KL
Topic – E9.3
Each student in a class of 20 students records the number of coins in their pockets.
The table shows the results:
Number of coins | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
---|---|---|---|---|---|---|---|
Frequency | 3 | 1 | 7 | 8 | 0 | 0 | 1 |
(a) Find the median.
(b) Calculate the mean.
▶️ Answer/Explanation
(a) Ans: 2
Median position = (20+1)/2 = 10.5th value
Cumulative frequencies: 3, 4, 11, 19 → median is 2
(b) Ans: 2.25
Total coins = (0×3)+(1×1)+(2×7)+(3×8)+(6×1) = 45
Mean = 45 ÷ 20 = 2.25
Topic – E4.6
The diagram shows three lines meeting at a point.
Find the value of w.
▶️ Answer/Explanation
Ans: 190
Angles on a straight line add up to 180°.
The angle opposite 80° is also 80° (vertically opposite angles).
w = 360° – (80° + 80° + 10°) = 190° (angles around a point).
Topic – E2.5
Solve the equation.
$7 – h = 3 – 5h$
▶️ Answer/Explanation
Ans: -1
$7 – h = 3 – 5h$
$-h + 5h = 3 – 7$
$4h = -4$
$h = -1$
Topic – E2.1
Sacha buys b books and m magazines.
The cost of each book is \$12 and the cost of each magazine is \$5.
Write an expression, in terms of b and m, for the total cost of the books and the magazines.
▶️ Answer/Explanation
Ans: $12b + 5m$
Cost of books = number of books × price per book = $12 × b$
Cost of magazines = number of magazines × price per magazine = $5 × m$
Total cost = Cost of books + Cost of magazines = $12b + 5m$
Topic – E4.6
Find the size of an interior angle of a regular 15-sided polygon.
▶️ Answer/Explanation
Ans: 156°
Sum of interior angles = (n-2) × 180° = (15-2) × 180° = 2340°
Each interior angle = Total sum ÷ number of sides = 2340° ÷ 15 = 156°
Alternatively: 180° – (360° ÷ 15) = 180° – 24° = 156°
Topic – E1.4
Without using a calculator, work out $2\frac{1}{4} – 1\frac{11}{12}$.
You must show all your working and give your answer as a fraction in its simplest form.
▶️ Answer/Explanation
Ans: $\frac{1}{3}$
Convert to improper fractions: $\frac{9}{4} – \frac{23}{12}$
Find common denominator (12): $\frac{27}{12} – \frac{23}{12}$
Subtract numerators: $\frac{4}{12}$
Simplify: $\frac{1}{3}$
Topic – E2.5
Solve the simultaneous equations.
$3p – 2q = 7$
$p + 2q = 1$
▶️ Answer/Explanation
Ans: p = 2, q = -½
Add both equations to eliminate q:
$(3p – 2q) + (p + 2q) = 7 + 1$ → $4p = 8$ → $p = 2$
Substitute p=2 into second equation:
$2 + 2q = 1$ → $2q = -1$ → $q = -½$
Topic – E2.2
$V = \sqrt[3]{\frac{x}{y}}$
Rearrange the formula to write x in terms of V and y.
▶️ Answer/Explanation
Ans: x = V³y
Start with V = ∛(x/y)
Cube both sides: V³ = x/y
Multiply both sides by y: x = V³y
Topic – E2.7
Find the nth term of each sequence:
(a) 21, 13, 5, -3, -11, …
(b) 2.5, 5, 10, 20, 40, …
▶️ Answer/Explanation
Ans:
(a) 29 – 8n
Common difference is -8, first term is 21, so nth term = 21 – 8(n-1) = 29 – 8n
(b) 5 × 2ⁿ⁻²
Geometric sequence with ratio 2, first term 2.5, so nth term = 2.5 × 2ⁿ⁻¹ = 5 × 2ⁿ⁻²
Topic – E4.7
(a)
A, B, C and D lie on the circle.
TAS is a tangent to the circle at A.
(i) Find the value of x.
(ii) Find the value of y.
(b)
P, Q and R lie on the circle, center O.
Find the value of w.
▶️ Answer/Explanation
Ans:
(a)(i) x = 41° (angle between tangent and chord equals angle in alternate segment)
(a)(ii) y = 37° (angles in same segment are equal)
(b) w = 130° (angle at center is twice angle at circumference)
Topic – E9.3
The box-and-whisker diagram shows information about the heights of some plants.
(a) Find the median height.
(b) Find the interquartile range of the heights.
▶️ Answer/Explanation
Ans:
(a) 28 cm (middle line of box plot)
(b) 33 cm (upper quartile – lower quartile = 45 – 12 = 33)
Topic – E6.5
Calculate the shortest distance from C to AB.
▶️ Answer/Explanation
Ans: 9.40 cm
Shortest distance is perpendicular from C to AB.
Using right triangle trigonometry: distance = BC × sin(33.14°).
Calculation: 17.2 × sin(33.14°) ≈ 9.40 cm.
Topic – E2.3
Simplify:
(a) $18x^{18} \div 3x^{3}$
(b) $(125y^{75})^{\frac{2}{3}}$
▶️ Answer/Explanation
Ans:
(a) $6x^{15}$
Divide coefficients: $18 ÷ 3 = 6$
Subtract exponents: $x^{18-3} = x^{15}$
(b) $25y^{50}$
Cube root first: $125^{\frac{1}{3}} = 5$ and $y^{75×\frac{1}{3}} = y^{25}$
Then square: $5^2 = 25$ and $(y^{25})^2 = y^{50}$
Topic – E4.4
Two mathematically similar solids have volumes 81 cm³ and 24 cm³.
The height of the smaller solid is 4.8 cm.
Calculate the height of the larger solid.
▶️ Answer/Explanation
Ans: 7.2 cm
Volume ratio is 81:24 = 27:8.
Linear scale factor is cube root of volume ratio: 3:2.
Height of larger solid = 4.8 × (3/2) = 7.2 cm.
Topic – E2.8
y is inversely proportional to √(x+2).
When x = 2, y = 3.
Find y in terms of x.
▶️ Answer/Explanation
Ans: y = 6/√(x+2)
General form: y = k/√(x+2).
Substitute x=2, y=3: 3 = k/√4 → k = 6.
Final equation: y = 6/√(x+2).
Topic – E6.4
Solve the equation tanx + 2 = 0 for 0° ≤ x ≤ 360°.
▶️ Answer/Explanation
Ans: 116.6°, 296.6°
Rearrange: tanx = -2.
First solution: x = tan⁻¹(-2) ≈ -63.4° → 180-63.4=116.6°.
Second solution: 116.6° + 180° = 296.6°.
Topic – E1.2
The Venn diagram shows the number of elements in each region.
(a) Use set notation to describe the shaded region.
(b) Find n(A ∩ B ∩ C).
▶️ Answer/Explanation
(a) Ans: (B ∪ C) ∩ A’
The shaded region represents elements in B or C but not in A.
(b) Ans: 5
This is the intersection of all three sets A, B, and C.
Topic – E6.6
The diagram shows a cuboid with a diagonal PB.
Calculate the angle between the diagonal PB and the base ABCD.
▶️ Answer/Explanation
Ans: 17.1°
First find diagonal BD using Pythagoras: √(12² + 5²) = 13 cm.
The angle is between PB and BD. Use tanθ = opposite/adjacent = height/BD = 4/13.
θ = tan⁻¹(4/13) ≈ 17.1°.
Topic – E2.2
Write x² + 8x – 7 in the form (x + a)² + b.
▶️ Answer/Explanation
Ans: (x + 4)² – 23
Take coefficient of x: 8 → half is 4.
Square it: 4² = 16.
Rewrite: x² + 8x as (x + 4)² – 16.
Final form: (x + 4)² – 16 – 7 = (x + 4)² – 23.
Topic – E1.10
A rectangle has an area of 150 m², correct to the nearest square metre.
The length of the rectangle is 22 m, correct to the nearest metre.
Calculate the upper bound of the width of the rectangle.
▶️ Answer/Explanation
Ans: 7 m
Upper bound of area = 150.5 m².
Lower bound of length = 21.5 m.
Upper bound width = max area/min length = 150.5/21.5 ≈ 7 m.
Topic – E2.3
Simplify:
$\frac{3x – 2 – 3xy + 2y}{1 – y^2}$
▶️ Answer/Explanation
Ans: $\frac{3x – 2}{1 + y}$
Factor numerator: (3x – 2)(1 – y).
Factor denominator: (1 – y)(1 + y).
Cancel common factor (1 – y).
Final simplified form: (3x – 2)/(1 + y).
Topic – E7.4
In the diagram, $\overrightarrow{OA} = a$ and $\overrightarrow{OB} = b$.
AK : KB = 2 : 1
OK = KC.
Find $\overrightarrow{AC}$ in terms of a and b.
Give your answer in its simplest form.
▶️ Answer/Explanation
Ans: $-\frac{1}{3}a + \frac{4}{3}b$
Find K’s position: $\overrightarrow{OK} = \frac{2}{3}b + \frac{1}{3}a$.
Since OK = KC, C’s position is $\overrightarrow{OC} = 2\overrightarrow{OK} = \frac{2}{3}a + \frac{4}{3}b$.
$\overrightarrow{AC} = \overrightarrow{OC} – \overrightarrow{OA} = (\frac{2}{3}a + \frac{4}{3}b) – a = -\frac{1}{3}a + \frac{4}{3}b$.