Q.4. (20p) Using the information given in table below, develop the following aggregate plan and calculate total cost of the plan. Jan 12000 26 Feb 14500 24 March 15000 26 April 20000 25 May June 30000 22000 27 22 Demand Forecast Number of Working Days by Month Safety Stock Policy is %10 of demand forecasts in each month Costs Inventory holding cost Marginal cost of stockout Marginal cost of subcontracting Labor hours required per unit Regular time cost (first 8 hours each day) Overtime cost $75 $25 $150 2 hours $50 $100 $ per unit per month $ per unit per month S per unit per unit $ per hour S per hour Plan: constant workforce (150 workers); not allowed to overtime and stockout; if necessary subcontracting is allowed to meet demands