The School of Business Has 3 Fax Machines

Multiple Choice

The school of business has 3 fax machines.The toner in each machine needs to be changed after about 5 hours of use.There is one unit secretary who is responsible for the fax machine maintenance.It takes him 15 minutes to replace the toner cartridge.What is the average waiting time in the queue?

A) .0142 hour
B) .1563 hour
C) .0249 hour
D) .2749 hour
E) None of the above