Refer to the Billy's Bank situation in Problem 13-24.

Billy is considering adding a second teller (who would work at the same rate as the first) to reduce the waiting time for customers, and he assumes that this will cut the waiting time in half. If a second teller is added, find

(a) The average time in the line.

(b) The average number in the line.

(c) The average time in the system.

(d) The average number in the system.

(e) The probability that the bank is empty.