I don't know how to write equations. Please formulate it and I'll solve in Lindo by myself.

A manufacturing firm would like to plan its production/inventory policy for the months of August, September, October, and November. The product under consideration is seasonal and its demand over the particular months is estimated to be 500, 600, 800, and 1,200 units, respectively. Presently, the monthly capacity of production is 600 units with a unit cost of $25. Management has decided to install a new production system with monthly capacity of 1,100 units at a unit cost of $30. However, the new system cannot be installed until the middle of November. The starting inventory at the beginning of August is expected to be 250 units and that at most 400 units can be stored during any given month. The holding inventory cost per month per item is $3. Assuming that the demand must be satisfied and 100 units in inventory are required at the end of November, management would like to determine the production schedule that minimizes the total production and inventory cost. Formulate an LP model to find the optimal production schedule and solve the model using LINDO