so there are 5/8 gallons and 4/5 walls to cover, so the wall/gallon rate will just be 45 ÷ 5/8.
[tex]\bf \cfrac{\quad \frac{4}{5}~wall\quad }{\frac{5}{8}~gallon}\implies \cfrac{4}{{5}}\cdot \cfrac{8}{{5}}\implies \cfrac{32}{25}~\cfrac{wall}{gallon}\implies 1.28~\frac{wall}{gallon}[/tex]
