5. Assume that the lifetime of a certain type and brand of TV is exponentially distributed with mean 8 years.

A. What's the probability a TV of this type and brand lasts longer than 6 years?

B. What's the probability a TV of this type and brand less than 7 years?

C. How long do 90% of TVs of this type and brand last?

PS. for part C, I am not sure it the result is 0.8 or 18. I got different and online people are posting different numbers. 0.8 nor 18 years made sense to me. Thanks