ABC Salon is a hair salon with two stylists, Mary and Mike. Each stylist can serve four customers per hour, on average, exponentially distributed. Six customers, on average, arrive at the salon every hour.

A. If all arriving customers wait in a common line for the next available stylist, how long would a customer wait in line, on average, before being served?

B. Suppose that 50% of the arriving customers want to be served only by Mary, and the other 50% want to be served only by Mike. How long would a customer wait in line, on average, before being served by Mary? By Mike? What is the average time a customer spends waiting in line?

C. Do you observe a difference in the answers to parts (a) and (b)? If so, explain.