Question

Find the indicated probability.

If P(A or B) = 0.8, P(A) = 0.4, and P(A and B)= 0.15, find P(B).
P(B)=
(Simplify your answer. Type an integer or a decimal.)

Answer 1

`P(B) = 0.55`

Explanation:

Given

`P(A\ or\ B) = 0.8`

`P(A) = 0.4`

`P(A\ and\ B) = 0.15`

Required

Find P(B)

In probability, we have:

`P(A\ or\ B) = P(A) + P(B) - P(A\ sd B)`

Substitute values

`0.8 = 0.4 + P(B) - 0.15`

Collect Like Terms

`P(B) = 0.8 - 0.4 + 0.15`

`P(B) = 0.55`