The Time Between Failures for an Electrical Appliance Is Exponentially

Multiple Choice

The time between failures for an electrical appliance is exponentially distributed with a mean of 25 months. What is the probability that the next failure will not occur before 30 months have elapsed?

A) not in excess of 0.2
B) in excess of 0.2 but not in excess of 0.3
C) in excess of 0.3 but not in excess of 0.4
D) in excess of 0.4 but not in excess of 0.6
E) in excess of 0.6