Queuing Problem: (Single servers model)

Customers arrive to a service facility on average 20 minutes apart

(exponentially distributed time between arrivals)

The average service time is 18 minutes per customer

(exponentially distributed service times)

1. What is the average server utilization?
2. What is the average number of customers waiting in line?
3. What is the average number of customers in the system?(Waiting in line + being served)
4. What is the average time (in minutes) spent waiting in line?
5. What is the average time (in minutes) spent in the system (Waiting in line + being served)