To represent how long an employee must work to make $80 at a rate of $20 per hour, we can set up a proportion using fractional notation. The appropriate proportion can be formed as follows:
\[ \frac{20}{1} = \frac{80}{x} \]
This means that for every $20 earned, it corresponds to 1 hour worked, and for $80 earned, it corresponds to \(x\) hours worked.
So the correct response is:
20 over 1 is equal to 80 over x.