The unit rate of a proportional relationship can be found by dividing a value of the dependent variable over the corresponding value of the independent variable.
In this case, the bushels of wheat depend on the number of acres. Then, divide the amount of bushels of wheat by the corresponding number of acres to find the unit rate. Use, for instance, that there are 140 bushels of wheat on 5 acres:
[tex]\frac{140}{5}=28[/tex]
Notice that the same unit rate is found when other pairs of data are used:
[tex]\begin{gathered} \frac{224}{8}=28 \\ \frac{420}{15}=28 \end{gathered}[/tex]
The equation of a proportional relationship between the independent variable x and the dependent variable y with a unit rate k, is:
[tex]y=kx[/tex]
If the unit rate k is equal to 28, then the equation that describes the relationship, is:
[tex]y=28x[/tex]
Therefore, the unit rate is equal to 28 bushels of wheat per acre, and the equation that describes the relationship, is:
[tex]y=28x[/tex]
