Exercise 11 Page 961

We want to determine whether the events are mutually exclusive and find the probability of their union. We will do these things one at a time.

Mutually Exclusive

Events that cannot occur at the same time are mutually exclusive. Mutually exclusive events have no outcomes in common. For example, because it is not possible to toss a coin and obtain heads and tails at the same time, these two events are mutually exclusive.

Rules for Probability
If $A$ and $B$ are mutually exclusive events, the probability that $A$ and $B$ will occur is $P (A and B) = 0 .$	If $A$ and $B$ are not mutually exclusive events, the probability that $A$ and $B$ will occur is $P (A and B) \neq = 0 .$

Let

A

be getting heads and

B

be getting tails on a coin.