A cafeteria serving line has a coffee urn from which customers serve themselves. Arrivals at the urn follow a Poisson distribution at the rate of 2.5 per minute. In serving themselves, customers take about 15 seconds, exponentially distributed.

a. How many customers would you expect to see on the average at the coffee urn? (Do not round intermediate calculations. Round your answer to 2 decimal places.)

Average no of customers

b. How long would you expect it to take to get a cup of coffee? (Round your answer to 2 decimal places.)

Expected time minute(s)

c. What percentage of time is the urn being used? (Do not round intermediate calculations. Round your answer to 1 decimal place.)

Percentage of time %