Answer:
1¹/₃₀
Explanation:
The 3 gallons were partially full
They contain 1/3 of a gallon and 1/5 and 1/2 of a gallon of paint.
the first is 1/3 of the gallon
the second is 1/5 of galloon
the third is 1/2 of gallon adding them together
1/3 +1/5 +1/2 = (10+6+15)/30 = 31/30 = 1¹/₃₀