probability

Question

if P(A)=1/2 , P(B)=0 then find P(A/B).

Answer 1

Note :

If both of the events A & B have positive probability, then independence is equivalent to the statement that the conditional probability of one event given the other is the same as the unconditional probability of the event.

P(A / B) = P(A) ⇔ P(B / A) = P(B) ⇔ P(A ∩ B) = P(A)P(B).

Given P(A) = 1 / 2, P(B) = 0.

P(A / B) = P(A)

             = 1 / 2.

Therefore, P(A / B) = 1 / 2.