Response to the following problem:
Zoro's Bistros is a chain of upscale, limited-item selfservice restaurants. During the dinner hours, the restaurant serves a $7.95 fixed-price dinner consisting of a choice of soup, main dish, dessert, and beverage. Since there are four food categories, management believes that customer service time can best be modeled using an Erlangian distribution with n = 4. Studies have indicated that the arrival process during dinner hours at Zoro's uptown location can be approximated by a Poisson distribution with λ = 40 customers per hour. The average time required to serve a customer is 1.2 minutes. There is a single waiting line, and customers are served on a first-come, first-served basis.
a. On the average, how many customers are waiting in line to begin being served at dinner time?
b. What is the average length of time a customer waits in line before being served at dinner time?