For the Billy's Bank situation in Problems 13-24 and 13-25, the salary and benefits for a teller would be $12 per hour. The bank is open 8 hours each day. It has been estimated that the waiting time cost per hour is $25 per hour in the line.

(a) How many customers would enter the bank on a typical day?

(b) How much total time would the customers spend waiting in line during the entire day if one teller were used? What is the total daily waiting time cost?

(c) How much total time would the customers spend waiting in line during the entire day if two tellers were used? What is the total waiting time cost?

(d) If Billy wishes to minimize the total waiting time and personnel cost, how many tellers should be used?