Jake's Roof Repair has provided the following data concerning its costs: Fixed Cost per Month $21,200 Wages and salaries Parts and supplies Equipment depreciation Truck operating expenses Rent Administrative expenses Cost per Repair-Hour $15.00 7.50 0.45 $1.80 $ 2,730 $ 5,770 $ 4,600 $ 3,880 $ 0.60 For example, wages and salaries should be $21,200 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 $52.00 per repair-hour