Answer:
x = 10
Step-by-step explanation:
Using the Pythagorean theorem:
8² + 6² = x²
64 + 36 = x²
x² = 100
x = 10
Amount is a function of what means
the amount is dependent on what variable
well, the amount of time to read would be depending on the number of pages or your reading speed
looking at the options, A is clearly the answer
A proportion looks like this:

It means that the quantity a,b,c and d are in the same proportion: the ratio between a and b is the same ratio between c and d.
They are particularly useful in situation when you have an example given, and you want to extrapolate the relationship for another couple.
For example, you can think of the following problem: "Five apples cost 2 dollars. How much will 8 apples cost?"
You can build the proportion

And then solve it for x:

X=1, x=-7 would be the correct answer.
Answer:
B
Step-by-step explanation:
(1/3)^-4
=1/[(1/3)^4]
=1/(1/81)
=81