In an I-phone service center, clients arrive at the service-in-charge counter at the average rate of 15 clients per hour.

The service-in-charge can serve an average of 20 clients per hour.

Required:

1. Compute for the average number of clients waiting in line to be served.

2. Compute for the average number of clients in the waiting line, not being served.

3. Compute for the average waiting time.

with solutions please!