To determine how long an employee must work to make $80 when they earn $20 per hour, you can set up the proportion using the relationship between earnings and hours worked.
Let \( x \) represent the number of hours worked. The amount earned is given by the equation:
\[ \text{Earnings} = \text{Hourly Rate} \times \text{Hours Worked} \]
In this case, the hourly rate is $20, and the earnings is $80. So, you can write the equation:
\[ 80 = 20 \cdot x \]
Now, to express this as a proportion in fractional notation, you can set it up as follows:
\[ \frac{20}{1} = \frac{80}{x} \]
Out of the provided options, the correct proportion that represents this relationship is:
20/1 = 80/x