Of all the Sunny Club members in a particular city, 25% prefer swimming on weekends and 75% prefer swimming on weekdays. It is f
ound that 10% of the members in that city prefer swimming on weekends and are female, while 55% of the members in that city prefer swimming on weekdays and are female. The probability that a club member picked randomly is female, given that the person prefers swimming on weekends, is
If we call by A the members that prefer swimming on weekends and by B the members that are women, we have that:
P(A) = 0.25
P(A and B) = 0.1
The probability of a member being female given that the person prefers swimming on weekends can be expressed as P(B|A) (that is, probability of B given A).