On an average every 4 minutes a person walks in assume the

Question

A flu clinic can manage 20 patients per hour. On an average, every 4 minutes a person walks in. Assume the M/M/1 queuing system. Find the following using the formulas discussed in class:

1. Average number of patients waiting in the clinic (excluding anyone who might be taking the flu shot).
2. The percentage of time the clinic will be busy.
3. Average time spent by the patient in the clinic (including waiting and flu shot time).
4. Average number of patients in the clinic (including the number of people taking the flu shot).
5. The probability that there will be three patients in the clinic.