For this case we must know the unit rate.
To do this, we divide the amount of area covered by the fertilizer, between time.
We have then:
[tex] r =\frac{\frac{5}{8}}{\frac{1}{4}}[/tex]
Then, rewriting the unit rate we have:
[tex] r =\frac{4*5}{8*1} [/tex]
[tex] r =\frac{20}{8} [/tex]
Answer:
the unit rate is:
[tex] r =\frac{20}{8}\frac{ft^2}{h}[/tex]