** PLEASE USE MICROSOFT EXCEL ONLY WITH FORMULAS***

Ashley's Department Store in Kansas City maintains a successful catalog sales department in which a clerk takes orders by telephone. If the clerk is occupied on one line, incoming phone calls to the catalog department are answered automatically by a recording machine and asked to wait. As soon as the clerk is free, the party that has waited the longest is transferred and answered first. Calls come in at a rate of about 12 per hour. The clerk is capable of taking an order in an average of 4 minutes. Calls tend to follows a Poisson distribution, and service times tend to be exponential. The clerk is paid $10 per hour, but because of lost goodwill and sales, Ashly's loses about $50 per hour of customer time spent waiting for the clerk to take an order. (a) What is the average time that catalog customers must wait before their calls are transferred to the order clerk? (b) What is the average number of callers waiting to place an order? (c) On average, how long does a customer spend on a phone call, from the moment of calling in to finishing the conversation? (d) What is the probability that the clerk is busy with talking to a customer? (e) What is the probability that when a customer calls in, there are two other callers waiting before him/her? (f) What is the total hourly cost of this queuing system based on the customer's time spent waiting to talk to the clerk? (g) Ashley's is considering to replace the current clerk with a more experienced clerk who can take an order in an average of 3 minutes, but requires a $15 hourly wage. Is it worthwhile to do so? Provide all the necessary computations to support your answer. For all questions, MUST show computational steps (e.g., excel formula or typed calculation). Providing only the final results will receive at least 50% penalty