Consider a phone that has no second line. When the phone is busy, the new callers get a busy signal. People call at the average rate of 3 calls per minute. The average duration of a telephone conversation is 40 seconds. The system behaves like a Bernoulli single-server queuing process with a frame size of 1 second. a. Compute the steady-state distribution for the number of concurrent calls. b. What is the probability that more than 180 people would attempt to call this number during one hour?