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 4.0 per minute. In serving themselves, customers take about 12 seconds, exponentially distributed.

a.
How many customers would you expect to see on the average at the coffee urn?
b.
How long would you expect it to take to get a cup of coffee?
c.
What percentage of time is the urn being used?
d.
What is the probability that three or more people are in the cafeteria?
e.
If the cafeteria installs an automatic vendor that dispenses a cup of coffee at a constant time of 10 seconds, how does this change your answers to a and b?

Depreciation on the company's equipment for 2017 is computed to be $18,000.the prepaid insurance account had a $6,000 debit balance at december 31, 2017, before adjusting for the costs of any expired coverage. an analysis of the company's insurance policies showed that $1,100 of unexpired insurance coverage remains. the office supplies account had a $700 debit balance on december 31, 2016; and $3,480 of office supplies were purchased during the year. the december 31, 2017, physical count showed $300 of supplies available. two-thirds of the work related to $15,000 of cash received in advance was performed this period. the prepaid insurance account had a $6,800 debit balance at december 31, 2017, before adjusting for the costs of any expired coverage. an analysis of insurance policies showed that $5,800 of coverage had expired. wage expenses of $3,200 have been incurred but are not paid as of december 31, 2017.

Suppose that in an economy the structural unemployment rate is 2.2 percent, the natural unemployment rate is 5.3 percent, and the cyclical unemployment rate is 2 percent. the frictional unemployment rate is percent and the actual unemployment rate (in this economy) is percent.

Gary lives in an area that receives high rainfall and thunderstorms throughout the year. which device would be useful to him to maintain his computer?