Q. Wednesdays opens a drive through with one cashier and one food preparer. Customers will first enter "place order" line to meet cashier and n enter "pick up" line to get food from food preparer. Currently, cashier can take an order in exactly 4 minutes and food preparer can prepare an order in exactly 3 minutes. During an hour, 12 customers arrive on average. Inter-arrival times are exponentially distributed.
a) What is average length of "place order line"? What is average length of "pick up line"?
b) What is average number of customers in drive through area?
c) Manager feels that cashier has slowed down process and send him to a strict training class. After class, cashier can take an order in exactly 2 minutes. What is capacity of system now?
d) After training, what is average length of "place order" line?