Suppose that John is the Service Centre head. John wants to base on costs to decide whether to add one staff member in the Service Centre. Suppose that a staff member's salary is 70,000 CAD per year, and there are a total of 260 working days per year. The cost per day is $269.23. However, because some factors have changed such as the arriving rate becomes higher, on the average, the waiting cost per day increases to $275.02. Since $269.23