The Chief Design Engineer for Colonial Warning Systems Wants to Know

Multiple Choice

The chief design engineer for Colonial Warning Systems wants to know the reliability of a two-lamp device intended to warn the operator of potential problems with a commercial steam kettle.One (either) lamp is to be lit if steam pressure drops below the desired level,and two (both) are to be lit if temperature drops below a desired level.His supplier estimates that a lamp has a failure rate of .2 per hour of operation,and a mean wear-out time of seven years with a standard deviation of eight months.If the temperature drops below the desired level,what is the probability the system will perform reliably for one hour?

A) .04
B) .40
C) .60
D) .64
E) .96