Please formulate. thanks!

SCHEDULING PROBLEM A company faces a firm schedule of delivery commitments for a product over the next 6 months. The production cost varies by month due to anticipated changes in material costs. The company's production capacity is 100 units per month on regular time and 15 units per month on overtime. The following are the delivery requirements and production costs per month: Month 1 Month 2 Month 3 Month 4 Month 5 Month 6 95 85 110 115 90 105 Delivery Commitmen ts(units) Cost per unit in $30 30 32 32 31 32 regular time Cost per $35 35 37 37 36 37 unit in Overtime The cost of carrying an unsold unit in stock is $2 per month. The problem for the company is to determine the number of units to produce in regular time and overtime each month to meet requirements at minimum costs. The firm has no units on hand at the start of month 1 and wishes to have no units on hand at the end of month 6. Hint: Use Xi as the number of units produced in regular time for month i and Yi as the number of units produced in overtime for month i and Ii as the number of units in stock (uns old) at end of month