In a doctor’s office, appointments to see a doctor are made at 15 minute intervals. But the amount of time the doctor spends with her patients are mostly less than 15 minute, but some of them may take...

In a doctor’s office, appointments to see a doctor are made at 15 minute intervals. But the amount of time the doctor spends with her patients are mostly less than 15 minute, but some of them may take much longer. It has been found that these times can be represented by an exponential distribution with mean 12 minutes. Assuming steady state, determine the expected number of patients in the waiting room at any time. Also, determine the mean amount of time a patient waits at the doctor’s office per visit. Suppose the office personnel and the doctor decide to take breaks when there are no customers in the system. During a 7 hour work day how often will they be able to take such breaks?