Customers at a bank wait in a single line for the next available teller. Customer arrivals can be modeled by a Poisson distribution that has a mean of 70 per hour during the midmorning hours. A teller can process an average of 100 customers per hour, which also can be modeled by a Poisson distribution. If there is one teller on duty, determine:

a. The average time a customer must wait in line for the letter.

b. The average number of customers waiting in line.

c. Average service time.

d. System utilization.

e. The probability of no customers waiting in line.

What values would be appropriate for the performance measures listed in the preceding problem for the case in which two tellers are available?