The pharmacy of a large metropolitan hospital is used exclusively for nurses' requests for medications. Medication requests occur at an average rate of 12 requests per hour. The time between consecutive requests, as well as the time to fill a prescription request follows an exponential distribution. Each pharmacist can process 15 requests hour. The pharmacy is staffed by two pharmacists who work independently of one another. The requests are collected in a common bin located on the counter the entrance to the pharmacy and are processed in first-come, first-served order. Assume that after submitting a request, each nurse waits at the counter until his/her order is filled. Round your answers to 2 decimal places. a. On the average, how many nurses would be at the counter, including those whose requests are in the process of being filled by a pharmacist? b. On the average, how long does each nurse wait at the counter? c. What is the probability that there are no nurses waiting at the pharmacy counter? d. Suppose that the cost to staff one pharmacist in the pharmacy is $27 per hour, and that this cost increases proportionally with the number of pharmacists. Suppose also that the cost to have a nurse waiting at the pharmacy is $24 per hour. Should the pharmacy be staffed with one, two or three pharmacists to minimize total cost?