Answer: 13.5 hours.
I got the answer by simply adding up the integers to start with.
Integers = 1, 2, 3 and 5.
The integers added up equal to 11.
Next we add up the remaining fractions.
Fractions = 1/2, 3/4, 3/4 and 1/2.
We can add up 1/2 and 1/2 to equal 1, and 3/4 and 3/4 to make 1.5.
1 + 1.5 = 2.5
Finally, we add up the answer for the integers and the fractions together, (11 + 2.5) which equals 13.5.
Our answer is 13.5 hours.
(Not sure why the answer isn't in the choices)
Step-by-step explanation:
Given,

and

Substitute x = 2 into expression.

Area under ALL probability distribution curves is 1.0, because all possible outcomes are taken into account.
(x-8)(x+5)
First thing you do is put the X's into the parentheticals because it is x^2 meaning there are 2 factors with x's. Then, you wonder what factors of -40 could add to get -3. In this case, they are -8 and 5. -8 times 5 is -40 and -8 +5 is -3. Then, you just add -8 and 5 beside the x's in the parentheticals.