$P(A) = 0.6$, $P(B) = 0.3$ and $P(A \cap B) = 0.1$. What is the probability that exactly one of $A$ and $B$ happens?

Explanation

1. 01

   Exactly one is $P(A \cup B) - P(A \cap B)$, that is $P(A) + P(B) - 2P(A \cap B)$.

2. 02

   $0.6 + 0.3 - 0.2 = 0.7$.