Probability: Mutually Exclusive Events

How to find the probability of independent events: formula, 1 example, and its solution.

Formula

Formula

Mutually exclusive events are the events
that cannot happen together.

So, if A and B are mutually exclusive events,
then P(A and B) = 0.

Recall that
P(A or B) = P(A) + P(B) - P(A and B).

Probability: A or B

P(A and B) = 0

So P(A or B) = P(A) + P(B).

Example

Example

Solution

Picking a blue marble (A)
and
picking a green marble (B)
cannot happen together.
(You can pick only one marble.)

Then these two events are
mutually exclusive events.

P(A) = 0.3
P(B) = 0.4

Then
P(A or B) = 0.3 + 0.4.

0.3 + 0.4 = 0.7

So 0.7 is the answer.