WAEC Mathematics Past Questions & Answers - Page 213

1,061.

What is the mode?

A.

22.5 years

B.

23.0 years

C.

24.0 years

D.

27.5 years

Correct answer is B

No explanation has been provided for this answer.

1,062.

What is the range of their age?

A.

14 years

B.

20 years

C.

30.5 years

D.

31 years

Correct answer is B

Range = 30.5 - 10.5

= 20 years

1,063.

If the probability that an event will occur is p and the probability that it will not occur is q, which of the following is true?

A.

p-q=1

B.

q-p=0

C.

p+q=1

D.

p+q=0

Correct answer is C

No explanation has been provided for this answer.

1,064.

A box contains 5 red, 3 green and 4 blue balls. A boy is allowed to take away two balls from the box. What is the probability that one is green and the other is blue?

A.

\(\frac{2}{11}\)

B.

\(\frac{5}{12}\)

C.

\(\frac{8}{12}\)

D.

\(\frac{7}{11}\)

Correct answer is A

Total number of balls = 5 + 3 + 4 = 12 balls

P(one ball is green and the other is blue) = P(first ball is green and second blue) + P(first ball is blue and the second green)

 = \(\frac{3}{12} \times \frac{4}{11} + \frac{4}{12} \times \frac{3}{11}\)

= \(\frac{2}{11}\)

1,065.

A box contains 5 red, 3 green and 4 blue balls. A boy is allowed to take away two balls from the box. What is the probability that the two balls are red?

A.

\(\frac{5}{33}\)

B.

\(\frac{5}{36}\)

C.

\(\frac{103}{132}\)

D.

\(\frac{31}{36}\)

Correct answer is A

Total number of balls = 5 + 3 + 4 

= 12 balls

P(first ball is red) = \(\frac{5}{12}\)

P(second ball is red) = \(\frac{4}{11}\)

\(\therefore\) P(both balls are red) = \(\frac{5}{12} \times \frac{4}{11}\)

= \(\frac{5}{33}\)