WAEC Mathematics Past Questions & Answers - Page 237

1,181.

Simplify log\(_7\) 8 - log\(_7\) 2 + log\(_7\) 4.

A.

0

B.

\(2log_7 2\)

C.

\(3log_7 2\)

D.

\(4log_7 2\)

Correct answer is D

log\(_7\) 8 - log\(_7\) 2 + log\(_7\) 4

= log\(_7\) (8/2 x 4)

= log\(_7\) 16

= 4 log\(_7\) 2

1,182.

The side of a rhombus is 10cm long, correct to the nearest whole number. Between what limits should the perimeter P lie?

A.

39cm ≤ P ≤41cm

B.

38cm ≤ P < 42cm

C.

38.5 ≤ P ≤ 41.5cm

D.

38.5 ≤ P ≤ 40cm

Correct answer is B

If the side = 10 cm, correct to the nearest whole number, then

The side ranges from 9.5 cm to 10.5 cm. (9.5 \(\leq\) s < 10.5)

Perimeter of a rhombus = 4 x side

\(\therefore\) 4 x 9.5 \(\leq\) perimeter < 4 x 10.5

= 38 cm \(\leq\) P < 42 cm

1,183.

Arrange in ascending order of magnitude \(26_8, 36_7, and 25_9\)

A.

\(25_9 26_8 36_7\)

B.

\(26_8 25_9 36_7\)

C.

\(36_7 26_8 25_9\)

D.

\(36_7 25_9 26_8\)

Correct answer is B

No explanation has been provided for this answer.

1,184.

The side of a square is increased from 20cm to 21cm. Calculate the percentage increase in its area

A.

2.5%

B.

9.3%

C.

10.0%

D.

10.25%

Correct answer is D

old area = 202 = 400
new area = 212 = 441
% increase in area \(=\frac{41}{400}\times \frac{100}{1}\\
=10.25\%\)

1,185.

A trader makes a loss of 15% when selling an article. Find the ratio, selling price : cost price

A.

3:20

B.

3:17

C.

17:20

D.

20:23

Correct answer is C

No explanation has been provided for this answer.