Here is the scenario;
Let's say that a wholesaler have a storage with the capacity of $75,000$ $m^3$. The stock of corn at the beginning of the year is $15.000$ $m^3$ and the working capital is $ 25,000$ USD. The regulation says that they cannot sell the corn bought in a particular month right away, it can only be sold in the next month. The revenue from selling the corn in a particular month can be used to purchase corn in the same month. Furthermore, they need to have at least $21,000$ $ m^3$ corn at the end of March.
The estimated sales and purchase in the next 3 months are :
Determine the purchases and sales policy for the next 3 months that contains the relationship between sales, purchases and stock level to maximize the working capital.
So my attempt is to choose the decision variables, which are the quantity of purchased corn, and the quantity of the corn for sale.
The parameters are the storage capacity, available working capital, initial corn stock, revenue each month, and the number of money spent each month to purchase some corn.
Is there anything missing here? I couldn't decide the constrains and determine the model. Could anyone please tell me how should I tackle this problem? I would appreciate any help!