Phone calls arrive at the rate of 48 per hour at the reservation desk of a Transport Office. (a) Compute the probability of receiving at least three calls in a 5-minute interval of time. (b) Compute the probability of receiving exactly 10 calls in 15 minutes. (c) Suppose no calls are currently on hold. If the clerk takes 5 minutes to complete the current call, how many callers do you expect to be waiting by that time? What is the probability that none will be waiting? (d) If no calls are currently being processed, what is the probability that the clerk can take 3 minutes for personal time without being interrupted by a call?