A manufacturer of heavy truck engines must develop a production plan, given the following demand forecasts for engine. The company currently has 13 workers and makes 130 engines per month. Regular labour cost is $500 per engine. The beginning inventory is zero. Overtime labour costs $750 per engine. Hiring cost is $3,000 per worker. Inventory holding cost is $50 per engine per month, and backorder cost is $250 per engine per month. Develop the minimum cost plan for this company. Hint. Start with level output/workforce plan, and use the trade-off analysis to show that changing this plan will only increase the total cost. (Negative answers should be indicated by a minus sign. Do not leave any empty spaces; input a "0" wherever required. Round the final answers to the nearest whole number. Round the "Average" answers to 1 decimal place.)