Question

Suppose S and T are mutually exclusive events. Find P(S or T) if P(S) = 29% and P(T) = 49%.

Answer 1

Mutually exclusive means that the intersection of the events is empty: P(S and T) = 0.

P(S or T) = P(S) + P(T) = 29% + 49% = 78%

If events S, T are not mutually exclusive, then P(S or T) = P(S) + P(T) - P(S and T)