344 9 Dynamic Programming The optimal solution is to plant two rows of tomato plants, one row of arti- chokes and one row of red peppers with a maximum scored obtained of 30. 9.11 Production Planning in a Recycled Glass Firm A supplier of recycled glass parts, MEDITERRASA, forecasts the demand of an article for the following 4 months of 100, 140, 210 and 180 units, respectively. The firm must hold only the sufficient stocks to meet the demand of each month, or it may hold some surplus stock to meet the demand of two or more successive months with a storage cost of $1.2 per month for each surplus stock unit. MED- ITERRASA calculates that the production costs for the following months, which varies depending on the units produced, is $15, $12, $10 and $14, respectively. A preparation cost of $200 is incurred each time a manufacturing order is done. The firm wishes to develop a production plan which minimises the total costs incurred by production orders, production and maintaining an article in the inventory. Formulate a dynamic programming model, provide tables with the posible states and decisions, and solve it to find an optimal solution