23 You are planning a bank. You plan for six tellers. Tellers take 15 minutes per customer with a standard deviation of 7 minutes. Customers arrive one every three minutes according to an exponential distribution (recall that the standard deviation is equal to the mean). Every cus- tomer that arrives eventually gets serviced.

a. On average how many customers would be waiting in line?

b. On average how long would a customer spend in the bank?

c. If a customer arrived, saw the line, and decided not to get in line, that customer has

d. A customer who enters the line but decides to leave the line before getting service is said to have