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.What warranty period for a lamp would give a probability of .9987 that it would not require warranty service?
A)5 years
B)5.67 years
C)6.33 years
D)7 years
E)9 years

Question

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The Answer of 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.What warranty period for a lamp would give a probability of .9987 that it would not require warranty service?
A)5 years
B)5.67 years
C)6.33 years
D)7 years
E)9 years

The Chief Design Engineer for Colonial Warning Systems Wants to Know