Jakes Roof Repair has provided the following data concerning its costs: Fixed Cost per Month Cost per Repair-Hour Wages and salaries $ 20,800 $ 15.00 Parts and supplies $ 7.40 Equipment depreciation $ 2,740 $ 0.35 Truck operating expenses $ 5,770 $ 1.50 Rent $ 4,650 Administrative expenses $ 3,840 $ 0.80 For example, wages and salaries should be $20,800 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 its sales to be $46.00 per repair-hour.