WAEC Mathematics Past Questions & Answers - Page 308

1,536.

Which of the following about a rhombus may not be true?

A.

The diagonals are equal

B.

The diagonals bisect the angles through which they pass

C.

The diagonals bisect each other

D.

The adjacent sides are equal

E.

Opposite angles are equal

Correct answer is A

No explanation has been provided for this answer.

1,538.

A box contains 2 white and 3 blue identical marbles. If two marbles are picked at random, one after the other without replacement, what is the probability of picking two marbles of different colors?

A.

2/3

B.

3/5

C.

2/5

D.

7/20

E.

3/10

Correct answer is B

Total number of marbles = 5; 1st pick = 2/5 2nd pick = 3/4; 3rd pick = 3/5; 4th pick = 2/4
∴ Probability of picking two marbles of different colors = (2/5 x 3/4) + (3/5 + 2/4) = 12/20 = 3/5

1,539.

If events X and Y are mutually exclusive, P(X) = 1/3 and P(Y) = 2/5, P(X∪Y) is

A.

0

B.

2/15

C.

4/14

D.

11/15

E.

1

Correct answer is D

P(X \(\cup\) Y) = \(\frac{1}{3} + \frac{2}{5}\)

= \(\frac{11}{15}\)

1,540.

If events X and Y are mutually exclusive, . P(X) = 1/3 and P(Y) = 2/5, P(X∩Y) is

A.

0

B.

2/15

C.

11/15

D.

4/15

E.

1

Correct answer is B

P(X \(\cap\) Y) = \(\frac{1}{3} \times \frac{2}{5}\)

= \(\frac{2}{15}\)