<h2>1.</h2>
Answer
A. 16
Explanation
We know that f(x) varies directly with x, so this is a problem involving proportions.
We know that when f(x) = 160 when x = 5 and f(x) = ? when x = 0.5; in other words:

Now, we can express our proportion as a fraction and solve for f(x):




We can conclude that
when 
<h2>2.</h2>
Answer
B. 6.25
Explanation
Just like before, we have a problem involving proportions, but this time is an inverse proportion since h(x) varies inversely with x.
First, lets set up our proportion just like before. We know that when h(x) = 50 when x = 0.25 and h(x) = ? when x = 2; in other words:

Now we can express our proportion as a fraction:

But remember that we are dealing with an inverse proportion here, so before solving for h(x) we need to flip the second fraction:




We can conclude that
when 