14 Benny the Barber (see Problem 13) is considering the addition of a second chair. Customers would be selected for a haircut on a FCFS basis from those waiting, Benny has assumed that both barbers would take an average of 20 minutes to give a haircut, and that business would remain unchanged with customers arriving at a rate of two per hour. Find the following infor- mation to help Benny decide if a second chair should be added:

a. The average number of customers waiting.

b. The average time a customer waits.

c. The average time a customer is in the shop.