Given the following forecast and steady regular output of 550 every month, what total cost would result if overtime is limited to a maximum of 40 units a month, and subcontracting is limited to a maximum of 10 units a month? Unit costs are: Regular output $20 Overtime $30 Subcontract $25 Average Inventory $10 Backlog $18 Month 1 2 3 4 5 6 Forecast 540 540 570 590 600 580