Question

Let A and B be two mutually exclusive events of a random experiment such that P(not A) = 0.65 and P(A or B) = 0.65, find P(B).

Answer 1

P(A) = 1 – P(not A) = 1 – 0.65 = 0.35

=>P(A) = 0.35

Again, P(A or B) = P(A) + P(B) – P(A and B)

Here P(A and B) = 0

(Events are mutually exclusive)

0.65 = 0.35 + P(B)

P(B) = 0.65 – 0.35

P(B) = 0.30

Answer 2

P(B) = 0.30

P(AUB)=P(A)+P(B)

AND P(A') = 1- P(A)