Question 1. Aggregate Planning (25 marks) Digital Tech. is a company that produces webcams used for recording or streaming the video on the Internet. The company would like to develop an aggregate production plan for the next six months from January to June. After conducting a comprehensive marketing research, the managers have obtained the following demand forecast for each month: January February March Aprile May 8004 20 600 20 9004 500 700 Demand forecast 204 204 204 Number of working days Besides, after discussing with the finance department, the managers have also summarized the cost information as follows: June $20/unit/month $45/unit $110/unit $500/worker $600/worker 5 hours/unite $25/hour $35/hour Inventory holding cost Marginal cost of stockout Marginal cost of subcontracting Hiring and training cost Layoff cost Production hours required Straight-time cost (first eight hours per day)