NECO Mathematics Past Questions & Answers - Page 30

146.

Given that the universal set U={14,15,16,17,18,19,20}, J ={16,19,20} and K= {14,15,18}, find (J' ∩ K')1.

A.

{17}

B.

{16, 17, 19, 20}

C.

{1, 4, 15, 17, 18}

D.

{14, 15, 16, 18, 19, 20}

E.

{14, 15, 16, 17, 18, 19, 20}

Correct answer is D

U = {14,15,16,17,18,19,20}

J' = {14,15,17,18}

K' = {16,17,19,20}

(J' \(\cap\) K') = {17}

(J' \(\cap\) K')' = {14,15,16,18.19,20}

147.

Two fair coins are tossed at the same time. what is the probability of getting a head?

A.

1

B.

\(\frac{3}{4}\)

C.

\(\frac{1}{2}\)

D.

\(\frac{1}{3}\)

E.

\(\frac{1}{4}\)

Correct answer is E

No explanation has been provided for this answer.

148.

If t varies inversely as the cube of s, and t = 24, when s = 3, find t when s = 2

A.

8

B.

24

C.

27

D.

81

E.

648

Correct answer is D

No explanation has been provided for this answer.

149.

The lengths of the sides of a triangle are 15m, 21m, and 28cm. What is the size of the angle facing the side 21m (correct to one decimal place)?

A.

85.7°

B.

47.5°

C.

41.4°

D.

38.2°

Correct answer is B

using cosine rule,

\(cos\theta\) = \(\frac{28^2 + 15^2 - 21^2}{2\times28\times15}\)

= \(\frac{568}{840}\)

\(\theta = cos^{-1}\)

= 47.5°

150.

If sin θ = 4/5 where 0° ∠ θ ∠ 900, what is the value of cos θ + tan θ?

A.

\(\frac{14}{15}\)

B.

\(\frac{29}{15}\)

C.

\(\frac{13}{8}\)

D.

\(\frac{144}{15}\)

E.

\(\frac{24}{5}\)

Correct answer is B

No explanation has been provided for this answer.