needing help with solving in Excel

6. Given the following forecast and cost information, determine the total cost of a plan that uses regular time production output of 600 units per month, overtime is used when needed up to a maximum of 60 units per month, and subcontracting is used if additional units are needed to meet the forecast. Month 1 2 3 5 6 Forecast 570 600 630 650 670 690 Regular time cost = $40 per unit Overtime cost = $60 per unit Subcontracting cost = $80 per unit Holding cost - $10 per unit per month Note: Holding costs for each month are calculated on the average inventory level and in U.S. dollars