Answer:
Unit rate at which Martin paints in walls per gallon is \(\frac{32}{25} wall/gallon\).
Explanation:
Rate is defined as ratio between two quantities with different units.
Gallons of paint used by Martin = \(\frac{5}{8}\) gallons
Portion of wall Martin wishes to pint = \(\frac{4}{5}\) wall
Rate at which Martin paints the wall:
\(Rate=\frac{\text{Portion of wall covered}}{\text{Paint used}}\)
\(Rate=\frac{\frac{4}{5} wall}{\frac{5}{8} gallon}=\frac{32}{25} wall/gallon\)
Unit rate at which Martin paints in walls per gallon is \(\frac{32}{25} wall/gallon\).