The inverse power rule model is sometimes used in accelerated stress testing. The model is defined..

The inverse power rule model is sometimes used in
accelerated stress testing. The model is defined by

where C and m are constants and v s = voltage at a high
stress level. Reliability decreases proportional to the inverse of a power of
the stress. Given the following test data, estimate the MTTF at a normal stress
level of 90 volts. Assuming a CFR, what is the one-year (24 hr/day)
reliability?