A raffle is held in a club in which 10 of the 40 members are good friends with the president. The president draws two winners.
a. If the two winners are drawn with replacement, what is the probability that a friend of the president wins each time?
b. If the two winners are drawn without replacement, what is the probability that a friend of the president wins each time?
c. If the two winners are drawn with replacement, what is the probability that neither winner is a friend of the president?
d. If the two winners are drawn without replacement, what is the probability that neither winner is a friend of the president?