Here is a similar problem.
I have a trucks that holds 20 cubic yards and I want to move 192 cubic yards of dirt. I want to use equal size, almost full loads, between 19 and 20 cubic yards per load. How many loads do I need and how many cubic yards per load?
If I try to use 19 cubic yards per load then I would need 192/19 = 10 loads, but this leaves a remainder of 2 cubic yards. To make equal size loads I can divide this remaining 2 cubic yards equally among the 10 loads. 2/10 is one-fifth so if I take 10 loads of size ninteen and a fifth cubic yards I can move all 192 cubic yards.
10 19 1/5 = 190 + 2 = 192 cubic yards.