Question

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

• A. 0.6
• B. 0.2
• C. 0.21
• D. None of these

Answer 1

The correct option is B 0.2

$P(\overline{A}\cap \overline{B})=P(\overline{A}\cup \overline{B})-1-P(A\cup B)$
Since A and B are mutually exclusive,
$P(A\cup B)=P\left(A\right)+P\left(B\right)$
Hence required probability $=1–(0.5+0.3)=0.2$