Jake's Roof Repair has provided the following data concerning its costs: Fixed Cost per Month Cost per Repair-Hour Wages and salaries $ 21,200 $ 15.00 Parts and supplies $ 7.20 Equipment depreciation $ 2,770 $ 0.45 Truck operating expenses $ 5,710 $ 1.70 Rent $ 4,630 Administrative expenses $ 3,900 $ 0.50