21. Refer to Problem 1.1 in the textbook. a) Solve Problem 1.1 as written in the textbook. b) What is the total cost, total revenue, and profit if the actual demand is 4000 units? c) Create an Excel model for the problems solved in Parts (a) and (b). (Take two screenshots of the excel model, one showing the solution and one showing the formulas used - you can press Ctrl ' to show the formula view in excel) d) How many units should be sold to make a monthly profit of 20% of the monthly lease. e) At what production cost would you be able to breakeven if the monthly demand is 1500 units? 1.1. The manager of a small firm is considering whether to produce a new product that would require leasing some special equipment at a cost of $20,000 per month. In addition to this leasing cost, a production cost of $10 would be incurred for each unit of the product produced. Each unit sold would generate $20 in revenue. Develop a mathematical expression for the monthly profit that would be generated by this product in terms of the number of units produced and sold per month. Then determine how large this number needs to be each month to make it profitable to produce the product