The chief design engineer for Colonial Warning Systems warned an operator of potential problems with a commercial steam pressure tank. One lamp is to be lit if steam pressure drops below the desired level and two (both) are to be lit if temperature drops below the desired level. The supplier estimates that a lamp has a failure rate of 0.2 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