Jakes Roof Repair has provided the following data concerning its costs: Fixed Cost per Month Cost per Repair-Hour Wages and salaries $ 21,000 $ 15.00 Parts and supplies $ 7.70 Equipment depreciation $ 2,730 $ 0.45 Truck operating expenses $ 5,740 $ 1.80 Rent $ 4,640 Administrative expenses $ 3,840 $ 0.40 For example, wages and salaries should be $21,000 plus $15.00 per repair-hour. The company expected to work 2,600 repair-hours in May, but actually worked 2,500 repair-hours. The company expects