Martin uses 5/8 of a gallon of paint to cover 4/5 of a wall. what is the unit rate at which martin paints in walls per gallon? a.1/2 wall per gallonb)32/25 walls per gallonc)1 7/25 walls per gallond)1 3/32 walls per gallon

You can easily solve this by setting up a proportion with walls on the top and paint on the bottom.  First we can find the decimal equivalent of each of those fractions to make things easier.  5/8 = .625 and 4/5 = .8.  .  What this is asking is "if 4/5 (.8) of a wall is covered by 5/8 (.625) of a gallon of paint, how many walls (x) will 1 gallon of paint cover?"  If we cross multiply we have .625x = .8 and x = 1.28 which is the same as 1 7/25 walls/1 gallon, choice C.