Loading [MathJax]/jax/output/HTML-CSS/jax.js

WAEC Mathematics Past Questions & Answers - Page 121

601.

A regular polygon of n sides has each exterior angle to 45^o. Find the value of n

Correct answer is B

Each interior angle = $\frac{360^o}{n}$

45^o = $\frac{360^o}{n}$

45^on = 360^o

n = $\frac{360^o}{45}$

= 8

602.

A cylindrical container has a base radius of 14cm and height 18cm. How many litres of liquid can it hold? correct to the nearest litre [Take $\pi = \frac{22}{7}$ ]

View answer & explanation

Correct answer is A

Volume of cylinder = $\pi r^2 h$

= $\frac{22}{7} \times 14^2$ x 14 x 18 = 22 x 28 x 18

= 11088cm³

1000cm³ = $\frac{1}{1000}$ x 11088cm³

= 11.088

= 11

603.

One of the factors of (mn - nq - n2 + mq) is (m - n). The other factor is?

(n - q)

(q - n)

(n + q)

(q - m)

View answer & explanation

Correct answer is C

mn - nq - n $^2$ + mq

mn - n $^2$ - nq + mq

(mn - n $^2$ ) (mq - nq)

n(m - n) + q(m - n)

= (n +q) (m - n)

604.

If a number is chosen at random from the set {x: 4 $\leq x \leq 15$ }. Find the probability that it is a multiple of 3 or a multiple of 4

$\frac{1}{12}$

$\frac{5}{12}$

$\frac{7}{12}$

$\frac{11}{12}$

View answer & explanation

Correct answer is C

set = 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

multiple of 3 = 6, 9, 12, 15

multiple of 4 = 4, 8, 12

Prob(multiple of 3 or 4) = Prob(multiple of 3) + pro(multiple of 4)

= $\frac{4}{12} + \frac{3}{12} = \frac{7}{12}$

605.

Solve the equation; 3x - 2y = 7, x + 2y = -3

x = 1, y = -2

x = 1, y = 3

x = -2, y = -1

x = 4, y = -3

View answer & explanation

Correct answer is A

3x - 2y = 7; Solve by elimination method

x + 2y = -3

3x - 2y = 7.....(i)

-3x + 6y = -9.....(ii)

-8y = 16

y = $\frac{16}{-8} = -2$

Put y = -2 into equation (i); 3x - 2y = 7

3x - 2(-2) = 7

3x + 4 = 7

3x = 7 - 4

3x = 3

x = $\frac{3}{3}$ = 1