WAEC Past Questions and Answers - Page 2393

11,961.

If log\(_x\) 2 = 0.3, evaluate log\(_x\) 8.

A.

2.4

B.

1.2

C.

0.9

D.

0.6

Correct answer is C

log\(_x\)2 = 0.3

log\(_x\)8 =  log\(_x\)2\(^3\) = 3 log\(_x\)2

= 3 x 0.3 

= 0.9

11,962.

In XYZ, |YZ| = 32cm, < YXZ 53\(^o\) and XZY = 90\(^o\). Find, correct to the nearest centimetre, |XZ|

A.

31 cm

B.

25 cm

C.

20 cm

D.

13 cm

Correct answer is B

Tan 52\(^o\) = \(\frac{32}{\text{|XZ|}}\)

|XZ| = \(\frac{32}{Tan 52^o}\)

= 25cm

11,963.

If 2\(^{a}\) = \(\sqrt{64}\) and \(\frac{b}{a}\) = 3, evaluate a\(^2 + b^{2}\) 

A.

250

B.

160

C.

90

D.

48

Correct answer is C

2\(^a\) = \(\sqrt{64}\)

2\(^a\) = 8

2\(^a\) = 2\(^3\)

a = 3

b = 3\(^a\)

b = 3 x 3 = 9

a\(^2\) + b\(^2\) = 3\(^2\) + 9\(^2\) 

= 9 + 81 = 90

11,964.

The total surface area of a solid cylinder 165cm\(^2\). Of the base diameter is 7cm, calculate its height. [Take \(\pi = \frac{22}{7}\)]

A.

7.5 cm

B.

4.5 cm

C.

4.0 cm

D.

2.0 cm

Correct answer is C

165 = 2 x \(\frac{22}{7}\) x \(\frac{7}{2}\) x h + 2 x \(\frac{22}{7}\) x \(\frac{7}{2}\) x \(\frac{7}{2}\)

165 = 22h + 77 

\(\frac{22h}{22} = \frac{88}{22}\)

height = 4cm

11,965.

Which of these values would make \(\frac{3p^-}{p^{2-}}\) undefined? 

A.

1

B.

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

C.

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

D.

-1

Correct answer is A

P\(^2\) - p = 0

p(p - 1) = 0

p = 0 or p = 1