Question

A new shopping mall is considering setting up an information desk manned by one employee. Based upon information obtained from similar information desks, it is believed that people will arrive at the desk at a rate of 30 per hour. It takes an average of 1.5 minutes to answer a question. It is assumed that the arrivals follow a Poisson distribution and answer times are exponentially distributed. Assume that the information desk employee earns $10 per hour. The cost of waiting time, in terms of customer unhappiness with the mall, is $10 per hour of time spent waiting in line. What is the total cost of waiting time over an 8-hour day? A. more than 140, less than or equal to 160 B. more than 160 C. more than 100, less than or equal to 120 D. more than 120, less than or equal to 140 E. more than 80, less than or equal to 100

Answer 1

The answer is B i.e. more than 160.

The explanation is as below:

So the answer cannot be A because the cost is not less than 160. The answer is neither C as 180 is not less than 120 nor it is D or E because the value is more than 140 and 100.