2. Joe's Deli (30 points)

The popularity of Joe's Deli has caused lines to form throughout the operation and customers to start grumbling about the length of time they must spend to get their shopping completed. Joe's process is quite simple; he has one employee who works at the deli counter preparing fresh-cut meats and cheeses for his customers, and one employee at the cash register who rings up the customers' purchases and accepts payment from the customers. On average, the deli counter employee spends 40 seconds with each customer and the cash register employee spends 30 seconds with each customer. Joe's Deli serves an average of 80 customers per hour.

(Assume that all service and interarrival times are distributed exponentially.)

1. (15 points) What is the average total throughput time (including both waiting and service time) for a customer at Joe's Deli (assume all customers must visit both the deli counter and the cash register, and that you don't have to worry about time moving between the stations)?