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%

We effectively rewrite the equation as

In order for the LHS to be defined, we need to restrict
, or
. Now, the LHS will vanish when the numerator is 0, which happens for

This value is indeed smaller than 4, so the solution is
.
Answer:
A
Step-by-step explanation:
Answer:
we conclude that the total number of perfect odd squares between 5 and 211 will be: 6
Step-by-step explanation:
Let us check by taking squares
As taking 14² = 256 would exceed 211, and 1² = 1 is smaller than 5.
Therefore, we conclude that the total number of perfect odd squares between 5 and 211 will be: 6
For every four miles Ariana drove, Jonathan drove seven miles