WAEC Mathematics Past Questions & Answers - Page 189

941.

Each interior angle of a regular polygon is 108°. How many sides has it?

A.

5

B.

7

C.

9

D.

14

Correct answer is A

The exterior angle of the polygon = 180 – 108 = 72°. The sum of exterior angle of the regular polygon = 360°
The number of sides \(=\frac{360}{72}=5\)

942.

Find the next two terms of the sequence 1, 5, 14, 30, 55, ...

A.

61,110

B.

67,116

C.

81,140

D.

91,140

Correct answer is D

\(1 + 2^2 = 5 + 3^2 = 14 + 4^2 = 30 + 5^2 = 55\)

\(55 + 6^2 = 91 + 7^2 = 140\).

91, 140 are the next two terms.

943.

lf \(log_q p= r\), express p in terms of q and r

A.

p =qr

B.

p =rq

C.

\(p = \frac{r}{q}\)

D.

p=qr

Correct answer is D

If \(log_q p\) = r convert from logarithm to indices
P = q\(^r\)

944.

If \(\frac{x}{a+1}+\frac{y}{b}\) 1. Make y the subject of the relation

A.

\(\frac{b(a-x+1)}{a+1}\)

B.

\(\frac{a+1}{b(a-x+1)}\)

C.

\(\frac{a(b-x+1)}{b+1}\)

D.

\(\frac{b}{a(b-x+1)}\)

Correct answer is A

If \(\frac{bx+y(a+1)}{b(a+1)}=1\\
bx + ya + y = ba + b; y(a+1) = ba+b-bx\\
y(a+1)=b(a+1-x); y = \frac{b(1+a-x}{a+1}\)

945.

Calculate the total surface area of a cupboard which measures 12cm by 10cm by 8cm

A.

1920cm2

B.

592cm2

C.

296cm2

D.

148cm2

Correct answer is C

otal surfaced area of a cupboard = lb + lh + bh
l = length h = height b = base
l = 12cm h = 10cm b = 8cm
T.S.A \(= (12 \times 8 \times 12 \times 10 + 8 \times 10)cm^\\
= (96 + 120 + 80)cm^2 = 296cm^2\)