Road Rambler sells running shoes and apparel through catalogs and online. A single salesperson handles calls during the $4-8$ a$.$m$.$ shift. During this time, calls arrive at a rate of $14$ per hour following a Poisson distribution. It takes the salesperson an average of four minutes to process each call. The variability in service times is exponentially distributed. All calls received while

the salesperson is busy are placed in a queue.