Test Index

WAEC Mathematics 2014 Paper

© africaexams.com

Question : 33

Total: 49

The probability of an event P happening is

\;\frac{1}{5}

and that of event Q is

\;\frac{1}{4}

. If the events are independent, what is the probability that neither of them happens?

$\;\frac{4}{5}$
$\;\frac{3}{4}$
$\;\frac{3}{5}$
$\;\frac{1}{20}$

Solution:

Concept:

Probability that neither of two independent events happens = product of their individual complement probabilities.

Explanation:

Given:

P(P) = \frac{1}{5}

and

P(Q) = \frac{1}{4}

.

Probability that P does not happen:

1 - \frac{1}{5} = \frac{4}{5}

Probability that Q does not happen:

1 - \frac{1}{4} = \frac{3}{4}

Since the events are independent, multiply these complements:

\frac{4}{5} \times \frac{3}{4} = \frac{12}{20} = \frac{3}{5}

Answer:

\frac{3}{5}

, which is option C.

© africaexams.com

Go to Question:

Prev Question

Next Question