Currently, Ocala operates its support center with one consultant. If the consultant is busy when a new customer call arrives, the customer hears a recorded message stating that all consultants are currently busy with other customers. The customer is then asked to hold and is told that a consultant will provide assistance as soon as possible. The customer calls follow a Poisson probability distribution, with an arrival rate of four calls per hour. On average, it takes 7.5 minutes for a consultant to answer a customer's questions. The service time follows an exponential probability distribution.

To improve customer service, Ocala Software Systems wants to investigate the effect of using a second consultant at its technical support center. What is the probability that a customer will have to wait for one of the consultants? If required, round your answer to four decimal places.

P_w = fill in the blank 1