11. A poll of twenty voters is taken to determine the number in favor of a certain candidate for mayor. Suppose that 70% of all the city's voters favor this candidate. Let X represent the number of voters in the sample who support the candidate.

(a) What is the probability that exactly 11 voters favor the candidate?

(b) What is the probability that more than 8 voters favor the candidate?

(c) If a new sample (this time containing 25 voters) is selected, what is the expected number of voters who will favor the candidate?

12. The number of customers served at a particular bank follows a Poisson distribution with an average of 5 per hour.

(a) What is the probability that exactly 6 customers will be served at the bank during a randomly selected one-hour period?

(b) What is the probability that at least 3 but fewer than 8 customers will be served at the bank during a randomly selected one-hour period?