Problem 13.18 Jose Martinez of El Paso has developed a polished stainless steel tortilla machine that makes it a "showpiece" for display in Mexican restaurants. His forecast of capacity and demand follows: 4 Month 3 140 1 140 5 2 170 210 220 Demand Capacity Regular time Overtime 140 10 150 30 150 20 150 20 160 10 Subcontracting: 80 units available over the 5-month period Beginning inventory: 0 units Ending inventory required: 10 units Costs Regular-time cost per unit Overtime cost per unit Subcontract cost per unit Inventory holding cost per unit per month $90 $125 $138 $4 Assume that backorders are not permitted. Using the transportation method, the total cost of the optimal plan is $ (enter your response as a whole number)