Find a target quantity to maximize its value (profit) or minimize its value (cost), and make corresponding plans on this condition.

Write this objective function first, then analyze the meaning of the problem sentence by sentence, write down every constraint (must be complete), and the rest need not be calculated by manpower. LINGO software is essential for modeling, which is dedicated to solving linear programming problems. Just use that thing to calculate.

Of course, what I said is equivalent to not saying it, but the topic is too long and it is more painful to analyze. So I'm really sorry, but you'd better analyze it yourself slowly.