Processing math: 100%

WAEC Mathematics Past Questions & Answers - Page 12

56.

A rectangle with width 34cm and area 3 38cm2. Find the length

A.

6cm

B.

412cm

C.

2 58cm

D.

12cm

Correct answer is B

The area of a rectangle = length ✕ width

: Length = area ÷ width → 3 38 ÷ 34

27843

= 412cm

57.

A local community has two newspapers: the morning tomes and the evening dispatch. The morning times is read by 45% of the households.  The Evening Dispatch is read by 60% of the households.  Twenty percent of the households read both papers.  What is the probability that a particular household reads at least one paper?

A.

0.45

B.

0.65

C.

0.85

D.

0.95

Correct answer is C

Note that the group that reads both papers is being counted twice.

    (percentages add up beyond 100%)

Let M = those reading the Morning Times,

       E = those reading the Evening Dispatch

P( M or E) = P(M) + P(E) – P(M and E)

          = 0.45 + 0.60 – 0.20 

          = 0.85

58.

Find the volume of a cone of radius 3.5cm and vertical height 12cm. [Take π = 22/7]

A.

15.5cm3

B.

21.0cm3

C.

142cm3

D.

154cm3

Correct answer is D

volume of a cone = π r2h → 1223.53.51237

= 154cm3

59.

The lengths of the parallel sides of a trapezium are 9cm and 12cm. If the area of the trapezium is 105cm2, find the perpendicular distance between the parallel sides.

A.

5cm

B.

7cm

C.

10cm

D.

15cm

Correct answer is C

Area of a trapezium = [a+b]h2 

105 = [9+12]h2 → 105 x 2 =21h

h = 21021 → 10cm

60.

Find the correct to two decimal places, the volume of a sphere whose radius is 3cm. [Take π = 227]

A.

72.57cm3

B.

88.12cm3

C.

10529cm3

D.

113.14cm3

Correct answer is D

Volume of sphere =  \(\frac{4πr^3}{3}\) →   \(\frac{4 x 22  x 3^3}{3}\)

7927

= 113.14cm3