WAEC Mathematics Past Questions & Answers - Page 43

211.

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

212.

Simplify: \(\frac{x^2 - 5x - 14}{x^2 - 9x + 14}\) 

A.

\(\frac{x - 7}{x + 7}\)

B.

\(\frac{x + 7}{x - 7}\)

C.

\(\frac{x - 2}{x + 4}\)

D.

\(\frac{x + 2}{x - 2}\)

Correct answer is D

\(\frac{x^2 - 5x - 14}{x^2 - 9x + 14}\)

\(\frac{(x - 7)(x + 2)}{(x - 7)(x - 2)}\)

= \(\frac{x + 2}{x - 2}\) 

213.

There are 8 boys and 4 girls in a lift. What is the probability that the first person who steps out of the lift will be a boy? 

A.

\(\frac{1}{6}\)

B.

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

C.

\(\frac{2}{3}\)

D.

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

Correct answer is C

Total number of people in the lift = 8 boys + 4 girls

= 12 people

probability that a boy comes out = \(\frac{8}{12}\) = \(\frac{2}{3}\) 

214.

If (0.25)\(^y\) = 32, find the value of y.

A.

y = - \(\frac{5}{2}\)

B.

y = -\(\frac{3}{2}\)

C.

y = \(\frac{3}{2}\)

D.

y = \(\frac{5}{2}\)

Correct answer is A

(0.25)\(^y\) = 32

2\(^{-2y}\) = 3\(^{2}\)

2 - 2y = 5 

y = - \(\frac{5}{2}\) 

215.

If 3p = 4q and 9p = 8q - 12, find the value of pq.

A.

12

B.

7

C.

-7

D.

-12

Correct answer is A

9p = 8q - 12

9p = 2(4q) - 12

9p = 2(3q) - 12

9p = 6p - 12

3p = -12 

p = -4

\(\frac{3 \times -4}{4} = \frac{4q}{4}\) 

q = 13

pq = -3 x -4 

= 12