The Readylite Company Produces a Flashlight Which Is Perfectly Reliable

Multiple Choice

The Readylite Company produces a flashlight which is perfectly reliable except for two components: the battery,which has a random failure rate of one in every five hours of operation; and the light bulb,which has a random failure rate of three in every ten hours.If the company includes a backup light bulb with each flashlight,what is the probability that the flashlight will perform reliably for one hour (excluding light bulb replacement time,if any) ?

A) 0.6720
B) 0.7280
C) 0.8736
D) 0.9100
E) 0.9600