4. The Hayes Company manufactures and sells several pooo u one of which is called a slip differential. The company normally sells 30 differential each month. At this activity level, unit costs are: Direct Materials Direct Labor $6.00 Fixed Manufacturing Overhead Variable Selling Expenses Fixed Selling Expenses $ 4.00 Variable Manufacturing Overhead$3.50 $ 9.00 $ 3.00 $ 1.00 An outside supplier has offered to produce the slip differentials for the Hayes Company, and to ship them directly to the Hayes Company's customers. The facilities now being used to produce the slip differentials would be available for rent. Net rental income would be $60,000 per month. Fixed manufacturing overhead would continue at 75 percent of its present level. The total fixed selling expenses of the company would be unaffected by this . decision. What is the maximum acceptable price quotation per slip differential from the outside supplier