Question $2$

In the book, the author gives an example of the customer service department at Biggs Department Store. They have a waiting room where customers are served on a first$-$come, first$-$served basis. Customers are served by three store representatives located in partitioned stalls. Review of the department for a $12-$month period shows that customers arrive every six minutes on average, and service takes $15$ minutes on average.

You will find formulas for P$0,$ P$1,$ Pw$,$ L$,$ Lq$,$ W$,$ and Wq on a separate Excel worksheet. You won't be able to change the formulas, but you can change the arrival rate, service rate, and number of servers.

Answers can be included below or submited separately on Canvas.

a$)$ What happens if someone calls in sick and there are only two representatives instead of $3?$ In other words, why did the formulas give us negative numbers?

b$)$ Trying values for $3,4,5,$ or $6$ representatives, and assuming that each new representative costs $$15$ for the hour, how many customer service representative should Biggs have in the department? Explain your answer in two to four sentences.