Given P(happening of an event A) = 0.5
and P(happening of an event B) = 0.3
It is also given that A and B are mutually exclusive events
⇒ P(A ⋂ B) = 0
Now, we have to find the P(neither A nor B)
= 1 – P(A ⋃ B)
= 1 – [P(A) + P(B)]
[Since, A and B are mutually exclusive]
= 1 – (0.5 + 0.3)
= 1 – 0.8
= 0.2