The parts department of a large automobile dealership has a counter used exclusively for mechanics' requests for parts. The time between requests can be modeled by a negative exponential distribution that has a mean of 2 minutes. A clerk can handle requests at a rate of 20 per hour, and this can be modeled by a Poisson distribution that has a mean of 20. Suppose there are 2 clerks at the counter. Use Table 18-4. a. On average, how many mechanics are waiting in line? (Round your answer to 3 decimals.) b. On average, how many mechanics would be at the counter, including those being served? (Round your answer to 3 decimals.) c. What is the average wait time for a mechanic? (Round your answer to 3 decimals.) d. If a mechanic has to wait, on average, how long will he have to wait for assistance? (Round your answer to 3 decimals.)