Conditional probability

Question

S and T are two events. P(S)= 0.5 and P(T)=0.7. Given that S and T are independent. Find P(S | S'∩T'). How do you get 0.231?

Answer 1

If S' denotes the complement of S (which is fairly standard notation), then events S and (S'∩T') are mutually exclusive, and thus the conditional probability P(S | S'∩T') = 0.