Question

A and B are two events such that P (A) ≠ 0. Find P (B|A), if A ∩ B = Φ.

Answer 1

P(B|A) = `(P(B ∩ A))/(P(A)) = (P(A))/(P(A)) = 1`

A ∩ B = Φ i.e, P(A ∩ B) = P(Φ) = 0

⇒ P(B ∩ A) =`(P(B ∩ A))/(P(A)) = 0/(P(A)) = 0`