An amplifier with a Constant failure rate has a reliability

An amplifier with a Constant failure rate has a reliability of 0.9 at the end of one month of operation. If an identical amplifier is placed in standby parallel, and there is a 3% chance of switching failure, what is the reliability of the parallel system at the end of ONE YEAR?

Solution

Reliability in Series = 1 - (1-R(t)) * Failure rate

Reliability at the end of one month = 1 - (1-0.9)*(0.03)    = 0.997

Reliability at the end of one year = Reliability at the end of one month^12

                                                = 0.997 ^ 12     = 0.96459