The lifetime of plasma and LCD TV sets follows an exponential distribution with a mean of 100,000

Question:

The lifetime of plasma and LCD TV sets follows an exponential with a mean of
100,000 hours. Compute the probability a television set:
a. Fails in less than 10,000 hours.
b. Lasts more than 120,000 hours.
c. Fails between 60,000 and 100,000 hours of use.
d. Find the 90th percentile. So 10% of the TV sets last more than what length of time?

Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...