WAEC Past Questions and Answers - Page 4085

20,422.

Simplify: \(\frac{4^{-\frac{1}{2}} \times 16^{\frac{3}{4}}}{4^{\frac{1}{2}}}\)

A.

1/4

B.

0

C.

1

D.

2

E.

4

Correct answer is D

\(\frac{4^{-\frac{1}{2}} \times 16^{\frac{3}{4}}}{4^{\frac{1}{2}}}\)

= \(\frac{16^{\frac{3}{4}}}{4^{\frac{1}{2}} \times 4^{\frac{1}{2}}}\)

= \(\frac{(2^4)^{\frac{3}{4}}}{4^{\frac{1}{2}} \times 4^{\frac{1}{2}}}\)

= \(\frac{2^3}{4}\)

20,423.

ln order to obtain a sound note of a high pitch from a wire stretched by a constant tension, the wire must be

A.

short and thick

B.

short and thin

C.

long and thick

D.

long and thin

Correct answer is B

No explanation has been provided for this answer.

20,424.

Which of the following stimuli are not perceived through the skin of mammals?

A.

Light

B.

Pressure

C.

Pain

D.

Heat

E.

Cold

Correct answer is A

No explanation has been provided for this answer.

20,425.

The nth term of a sequence is given by (-1)\(^{n-2}\) x 2\(^{n-1}\). Find the sum of the second and third terms.

A.

-2

B.

1

C.

2

D.

6

E.

12

Correct answer is A

when n = 2

(-1)\(^{n-2}\) 2\(^{n+1}\) = 2

When n = 3

(-1)\(^{n-2}\) 2\(^{n+1}\) = -4

Sum = 2 - 4 = -2