JAMB Mathematics Past Questions & Answers - Page 100

496.

Given that Z = {1,2,4,5} what is the power of set Z?

A.

16

B.

8

C.

10

D.

12

Correct answer is A

Z has 4 elements, power = number of subset = 2p

Z = 2n = 24

= 16

497.

The probability of an outcome A is 1/6 . The probability of the B outcome is 1/4 . If the probability of A or B or both is 1/12 . What is the probability of both outcomes A and B?

A.

1/2

B.

1/3

C.

2/5

D.

3/4

Correct answer is B

Prob.(A outcome) = \(\frac{1}{6}\), Prob.(B outcome) = ¼

P(A ∪ B) = 1/12, Prob.(A ∩ B)

Prob.(A ∩ B) = Prob.(A) + Prob.(B) − Prob.(A ∪ B)

1/6 + 1/4 − 1/12

= (2 + 3 − 1) ÷ 12

= 4/12

= 1/3

Prob.(A ∩ B) = 1/3

498.

The volume of a cone (s) of height 6cm and base radius 5cm is

A.

157cm3

B.

155cm3

C.

175cm3

D.

145cm3

Correct answer is A

V = ⅓ πr2 h

Volume of a cone (Vc) = ⅓ × 3.14 × (5)2 × 6

= 156.93

157cm3

499.

The area of an ellipse is 132cm2.The length of its major axis is 14cm.Find the length of it minor axis

A.

10.5cm

B.

5cm

C.

10cm

D.

3cm

Correct answer is D

No explanation has been provided for this answer.

500.

The area of a circle of radius 4cm is equal to (Take π = 3.142 )

A.

10.3cm2

B.

15.7cm2

C.

50.3cm2

D.

17.4cm2

Correct answer is C

Area of a circle (A) = πr2

Radius = 4cm

π = 3.142

A = 3.142 × (4)2

= 3.142 × 16

= 50.272

A = 50.3cm2 (1dp)