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 20 minutes anda standard deviation of 4 minutes. Theservice time per customer has a mean of 15 minutes and a standarddeviation of 5 minutes. The waiting cost is$200 per customer per hour. The server cost is $25 per server perhour. Assume general probabilitydistribution and no buffer capacity restriction.a. Find the optimal number of servers to be employed to minimizethe total of waiting and server costs. (Ans:Cost per hour with one server=$59.00; Cost with 2 servers = $52.19;Cost with 3 servers = $75.40: So twoservers are optimal.)b. Find the average waiting time and the average total time throughthe system for the optimal case. (waiting:0.2188 min; Total: 15.2118 min)c. Find the cost per hour, average waiting time, and average flowtime for one server if the probabilitydistributions for the interarrival time and service time areassumed to be exponential and the mean valuesremain the same. The cost data remain the same. Use manualcalculations. (Ans: Cost per hour=$475.00,Waiting time=45.00 min, Flow time=60.00 min).