3. At a BPH walk-in clinic, patients arrive every 15 minutes on average (negative exponential distribution), and it takes about 10 minutes for the physician to diagnose the patient (negative exponential distribution). a. What are and ? b. On average, how long do patients wait to see the physician? c. On average, how many patients are there at the clinic? d. In an 8-hour day, how many hours is the physician idle? e. What is the probability that there are more than five patients at the clinic