Section 18.3 indicates that a linear waiting-cost function yields E(WC) CwL, where Cw is the cost of waiting per unit time for each customer. In this case, the objective for decision model 1 in Sec. 18.4 is to minimize E(TC) Css  CwL. The purpose of this problem is to enable you to explore the effect that the relative sizes of Cs and Cw have on the optimal number of servers.

Suppose that the queueing system under consideration fits the M/M/s model with 8 customers per hour and  10 customers per hour. Use the Excel template in your OR Courseware for economic analysis with the M/M/s model to find the optimal number of servers for each of the following cases.

(a) Cs $100 and Cw $10.

(b) Cs $100 and Cw $100.

(c) Cs $10 and Cw $100.