Answer:
7/12 of a gallon of yellow paint, 1/2 of a gallon of green paint and 1/8 of blue paint.
Explanation:
you change 3/4 to 9/12 to subtract it from 1 1/3 and then you change it back ti 3/4 to subtract it from 1 1/4 and for 7/8 you change it to 6/8 which would give you 7/12, 1/2 and 7/8 of a gallon.