## Mutually Exclusive Events

Two or more events are called mutually exclusive if the occurrence of any one event excludes the remaining events from occurring. For example, if A and B are mutually exclusive events, P(A ∩ B) = 0. Consequently, for two events A and B:

P(A ∪ B) = P(A) + P(B) − P(A ∩ B) becomes

P(A ∪ B) = P(A) + P(B)

or generally for any number of events:

P(A ∪ B ∪ C ∪...) = P(A) + P(B) + P(C) + ...

P(A ∪ B) = P(A) + P(B)

or generally for any number of events:

P(A ∪ B ∪ C ∪...) = P(A) + P(B) + P(C) + ...