Mutually Exclusive Events

Mutually Exclusive Events

How to solve mutually exclusive events problems: formula, example, and its solution.

Formula

If two events cannot happen together, then P(A and B) = 0. These two events are called mutually exclusive events. Then P(A or B) = P(A) + P(B).

Mutually exclusive events are the events
that cannot happen together.
P(A and B) = 0.

So if A and B are mutually exclusive events,
then P(A or B) = P(A) + P(B).

Example

A bag is filled with 15 colored and shaped cards. In selecting a card without looking, find the probability of selecting a triangle card or a white card.

There's no triangle and white card.

So selecting a triangle card
and selecting an white card
are mutually exclusive events.

So P(A and B) = 0.

P(A or B) = P(A) + P(B) = 4/15 + 7/15.