Solve:

We need to isolate k, so multiply both sides by the denominator, which is 64. When we do that, the fraction will cancel and we get:

If you want to check, plug in your answer to the original equation and see if it is true:


This statement is true, so
.
15 meters should be about right. hope this helped
The exponential distribution is:

where

The probability we want is how likely will a dvd player last more than 8 years, given it has already lasted 5 years
To find this, you use conditional probability.

where A is P(x>8) and B is P(x>5)
To find these probabilities, integrate over the distribution:

Sub into conditional probability formula:

Final Answer: Given a dvd player is more than 5 years old, the probability that it will last another 3 more years is about 54.9%