Maximum 3*x*24+ 16*y*4
Constraints.
X+Y≤50
3X≤ 100
12X+8Y≤480
As for milk, it doesn't have to be produced in a whole barrel, but it can be poured out separately without being put together. If you want to round, you can, and you need to add rounding constraints.
After the objective function and constraint conditions are known, they can be solved by LINDO software or matlab or hand-drawn linear programming.
X=20，Y=30
The following three question marks can be solved by setting several other variables 0- 1, which are omitted here. If you really can't do it, you can ask. Thank you.