1) The unit rate compares an increase in y with increases in x.
2) To find the unit rate, choose two points. Let's choose (20, 400) and (60, 1200).
3) The unit rate (r) will be the difference in x divided by the difference in y:
[tex]r=\frac{1200-400}{60-20}[/tex]
4) Now you can find r by solving the division.
[tex]\begin{gathered} r=\frac{800}{40} \\ r=20 \end{gathered}[/tex]
Answer: The unit rate is $20/foot.
Alternative C.
