In Excel: At a single-phase, multiple-channel service facility, customers arrive randomly. Statistical analysis of past

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In Excel: At a single-phase, multiple-channel servicefacility, customers arrive randomly. Statistical analysis ofpastdata shows that the interarrival time has a mean of 5 minutes andis exponentially distributed. The servicetime per customer has a mean of 4 minutes and is exponentiallydistributed. The arrival buffer capacity is 5customers. The lost customer cost due to blocking is $200 percustomer. The waiting cost is $100 percustomer per hour. The server cost is $20 per server per hour. UsePerformance.xls spreadsheet for queueanalysis and manual calculation for costs.a. Find the optimal number of servers to be employed to minimizethe total of lost customer cost, waiting cost,and server cost. (Ans: Cost per hour with one server=$318.77; Costwith 2 servers = $58.00; Cost with 3servers = $62.00: So two servers are optimal.)b. Find the average overall waiting time and the average total flowtime through the system for the optimalcase. (Ans: Waiting time: 0.73 min; Flow time: 4.73 min)