The correct answer is the third option. I just got it correct.
5/8
6/3
7/10
These are all the answers 4/8 is 1/2 and 5/8 is over it there is no half of 3 but 6/3 is 2 and 2 is a whole number it's over 1/2
5/10=1/2 and 7/10 is over it 1/4 isn't an answer because 2/4=1/2 6/12=1/2 but it says over 1/2 and finally 5/12 isn't it because like I said above 6/12 is 1/2
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%