Question

The probability of happening of an event A is 0.5 and the of B is 0.3 .If A and B are mutually exclusive events, then the probability of neither A nor B is

• A. 0.4
• B. 0.5
• C. 0.2
• D. 0.9

Answer 1

Answer: (C)

0.2

Answer 2

Given $P(A) = 0.5, P(B) = 0.3$
P(neither A nor B) $= P(A' \cap B')$
$= P(A \cup B)'$
$= 1 - P(A$\cup$B)$
$= 1 - [P(A) + P(B)]$ (because A and B are mutually exclusive events)
$= 1 - 0.8 = 0.2$