If 40% of the students of a class like football, 75% of the students like basketball, and 30% like both. If a student is picked at random who likes at least one of these games, what is the probability that he likes only football?
% of students who likes only football=40-30=10
% of students who likes at least one game=40+75-30=85
Required probability = P(Students likes only football) / P(Students who likes at least 1 game) = 10/85 = 2/17