Question

The neighborhood Clinkos Store has a single copy machine. The copier has been observed to serve on average 16 customers per hour during peak periods when it is never idle; the service time of this copier is exponentially distributed. Customers arrive at the copier according to a Poisson process with a mean of 12 customers per hour.

8. What is the coefficient of variation of the service time? If your answer is not an integer, provide at least three decimal places, e.g., 7.500.

9. What is the average service time of the copier in minutes? If your answer is not an integer, provide at least three decimal places, e.g., 7.500.

10. For an average customer of the copy machine, what is the expected waiting time in minutes before getting to use the copy machine? If your answer is not an integer, provide at least three decimal places, e.g., 7.500.

11. On average, how many customers do you expect to see waiting in the queue (not being served at the copier)? If your answer is not an integer, provide at least three decimal places, e.g., 7.500.

12. If Clinkos introduces a new machine which processes customer jobs twice as fast as the original machine (with service times still following an exponential distribution), how does the average customer’s total time in the store compare to the original time?

a. The new time is less than half of the old time

b. The new time is exactly one half of the old time

c. The new time is more than half of the old time

d. Does not change

Answer 1