Question

If P(A) = 0.8, P(B) = 0.5 and P(B|A) = 0.4, find  P(A ∪ B)

Answer 1

It is given that P(A) = 0.8, P(B) = 0.5, and P(B|A) = 0.4

P(A∪B) = P(A) + P(B) − P(A∩B)

⇒P(A∪B)=0.8 + 0.5 − 0.32 = 0.98