Eye Clinic

Patients arrive at an eye clinic according to a Poisson process, with a mean of six per hour. There are three doctors on duty, and the testing times for patients are distributed exponentially, with a mean of 20 minutes. Find the average number of people waiting and the average amount of time spent by a patient at the clinic.

    
The average number of people waiting in the queue:
Average time in minutes spent by a patient at the clinic: