Fresh Mart is a popular grocery store in Portland, which operates all day. During the late night shift customers arrive at the checkout counters according at 15 customers per hour. The management wants to operate only a single cashier during the late night shift. (Assume Cva=Cvp=1)
a) If the time a customer spends at the cashier (waiting + paying) is 12 minutes on average, what is the average service time at the cashier?
b) What is the current average waiting time?
c) What's the probability that on any given moment, more that two customers are waiting for the cashier to take them. To reduce the number of customers in queue, the manager decides to hire 1 more cashier.
d) What is the effect of this new hire in Tq?
e) By reducing waiting time, Fresh mart becomes more popular and more customers go to their store because of their fast service. Assume that the new demand rate increases to 40 customers/hr. What do you propose to do in this situation?