$P(A) = 0.6$, $P(B) = 0.5$ and $P(A \cap B) = 0.3$. What is the probability that neither $A$ nor $B$ happens?

Explanation

1. 01

   $P(A \cup B) = 0.6 + 0.5 - 0.3 = 0.8$.

2. 02

   Neither means the complement of $A \cup B$: $1 - 0.8 = 0.2$.