To find how long an employee must work to make $80 when paid $20 per hour, you can set up the following proportion:
Let \( x \) be the number of hours worked. The total amount earned ($80) is equal to the hourly wage ($20) multiplied by the number of hours worked \( x \). This gives us:
\[ \frac{20}{1} = \frac{80}{x} \]
So, the correct response using fractional notation is:
20 over 1 is equal to 80 over x.