please do in excel and show all formulas

Problem 1 Given the demand information and the level production plan given in the Excel spreadsheet, prepare an aggregate plan that minimizes the total cost. Regualar time production=$20 per unit Overtime production=$30 per unit Inventory holding cost=$3 per unit per period on average inventory Back orders=$10 per unit per period Note that, due to the labor union regulations, the overtime limit is 80 units per period. All demand has to be met by the end of the planning horizon. Pease use Excel Solver to find the optimal solution