Question

Given that A and B are two mutually exclusive events, find P (A or B) for the following:P(A) = 0.45 and P(B) = .39

Answer 1

In general,

$P(A\text{ or B)=P(A)+P(B)-P(A and B)}$

However, since we have two mutually exclusive events, they can't both occur at the same time, so

$P(A\text{ and B)=0}$

So in this case,

$P(A\text{ or B)=0.45+0.39-0=}0.84$

and so, P(A or B)=0.84