Question
The probability of A solving a problem is 
and that of B solving it is 
What is the probability that
(i) at least one of them will solve the problem?
(ii) Only one of them will solve the problem?
Solution
Let E denote the event ‘A solves the problem’ and F denote the event ‘B solves the problem’.
(i) P(none of them solves the problem) =
(ii) P(only one solves the problem) =
(i) P(none of them solves the problem) =
(ii) P(only one solves the problem) =
