1 Staffing at the Optimal Utilization A large grocery store is attempting to staff its check-out registers. Currently, the arrival rate is X=320 customers per hour, each server has a service time of E(T) = 3.75 minutes on average, and the interarrival and service times follow an exponential distribution. What is the distribution of the interarrival time A? d. 0.90 Considering any one of the individual s* queues, derive the expected number of customers waiting in line. a. 3.2 customers b. 8.1 customers c. 2.25 customers d. 0.9 customers For any one of the individual queues, what is the expected waiting time (minutes) spent in line for a customer? a. 15 minutes