Question: In an outpatient clinic, patients are kept in observation in a primary recovery room for 90 minutes after surgery and then they care sent home or moved to a secondary recovery room. Meanwhile, if a just-operated patient cannot be moved to a primary recovery bed (because all beds in the primary recovery room are occupied), the patient stays in the surgical bed, thus blocking it and precluding other operations from taking place (which, of course, decreases revenue and annoy the surgeon waiting to operate). The clinic has four surgical units. At peak time, an average of six (6) patients arrive per hour to the primary recovery room.

a. If the primary recovery room has a capacity of twelve (12) beds, what is the probability that a surgical bed will be temporarily blocked?

b. What should be the bed capacity of the primary recovery room if management wants to be sure than 98% of all operated patient will not need to wait for a primary recovery room bed?