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 probability that 2 fax machines need toner at the same time?

A) .8576
B) .1286
C) .0129
D) .1415