Calls arrive at Lynn Ann​ Fish's hotel switchboard at a rate of 2.0 per minute. The average time to handle each is 15 seconds. There is only one switchboard operator at the current time. The Poisson...

Calls arrive at Lynn Ann​ Fish's hotel switchboard at a rate of 2.0 per minute. The average time to handle each is 15 seconds. There is only one switchboard operator at the current time. The Poisson and negative exponential distributions appear to be relevant in this situation.​ The probability that the operator is busy​ =.50  What is  The average time that a caller must wait before reaching the operator​ =  minutes​ (round your response to two decimal​ places).