## Info

of service. Therefore, assuming that the store opens at 8:00 a.m., the first customer arrives at the checkout facility at approximately 8:00 a.m. and leaves at 8:12, after requiring 12 minutes of service at the checkout counter. The second pair of points are 32 and 1. The first number, 32, indicates that the second customer arrives 12 minutes after the first customer, at 8:12. But since the first customer is through the service facility at 8:12, the second customer will not have to wait. His 10 minutes of service at the checkout counter will begin at 8:12 and he will finish at 8:22. The third customer arrives at the same time as the second customer and requires 12 minutes service. But since the second customer is in the service facility, the third customer must wait in the queue until 8:22 before entering the service facility. Therefore, his waiting time is 10 minutes and he leaves the service facility at 8:34 (8:22 + 12 minutes service). The fourth customer arrives 15 minutes after the third customer (at 8:27) and requires 20 minutes service. Since the service facility is occupied until the third customer leaves at 8:34, the fourth customer must wait seven minutes in the queue. This process is repeated for 16 customers and the results are shown in Table 17-10.

The fourth step in the process is the final analysis of the data. The data shown in Table 17-10 consisted of 16 customers processed in the first four hours. The summation of the waiting time for the four hours is 230 minutes. Since the store is open for 12 hours, the total waiting time is 3 X 230, or 690 minutes. At \$50.00 per hour loss of good will, the manager loses approximately \$575 per 12-hour day because of waiting-line costs. The manager can put in a second service counter. If he pays the worker \$60.00 per hour burdened for a 12-hour day, the cost will be \$720.00. Therefore, it is more economical for the manager to allow people to wait than to put in a second checkout facility.