Aisha works at the local Yourizon store on Friday nights, usually with two other employees. This Friday, her boss has told her she will be the only sales associate present. Aisha wants to convince the manager that having only one worker on duty will result in dissatisfied customers and lost business. She pulls out her OM textbook and flips to the chapter on queuing.

a. If customers arrive at an average rate of 12 customers per hour and can be served at a rate of 15 customers per hour, will any customers have to wait? Why or why not?

b. Yourizon policy states that the average time a person waits in line for service should be no longer than 10 minutes. Does Aisha have a case?

c. The manager is averse to idle employees. What is the probability that Aisha will be idle on Friday night at the store?

d. Yourizon has learned that when there are more than three customers in the store at any time, new customers passing by will not enter. What is the probability that the average number of customers in the system is more than three?