Problem 1 (Integer programming model) ( pts.) The Research and Development Division of the Progressive Company has been developing four possible new product lines. Management must now make a decision as to which of these four products actually will be produced and at what levels. Therefore, an operations research study has been requested to find the most profitable product mix. A substantial cost is associated with beginning the production of any product, as given in the first row of the following table. Management's objective is to find the product mix that maximizes the total profit (total net revenue minus start-up costs). Product 2 3 $40000 $70000 $60 $90 $50000 Start-up Cost Marginal revenue 4 $60000 $80 $70 Let the continuous decision variables 21, 22, 23, and x4 be the production levels of products 1, 2, 3, and 4, respectively. Management has imposed the following policy constraints on these variables: No more than two of the products can be produced. Either product 3 or 4 can be produced only if either product 1 or 2 is produced. Only one of the constraints is applicable: either 5x1 + 3x2 + 6x3 + 4.2 4