Question

Given that P(A)=0.5 and p(AUB)=0.6 find the P(B) if P(A/B) =0.4?

Answer 1

First we have to find p(AnB)
P(A/B)=p(AnB)/p(A)
P(AnB)=p(A) x p(A/B)
P(AnB)=0.5 x 0.4 = 0.2
Then to find p(B)
P(A∪B) = P(A) + P(B) - P(A∩B)

P(A∪B) = 0.5+p(B)-0.2
0.6=0.3+p(B)
P(B)=0.6-0.3=0.3