Jakes Roof Repair has provided the following data concerning its costs:

	Fixed Cost per Month	Cost per Repair-Hour
Wages and salaries	$ 21,300	$ 16.00
Parts and supplies		$ 7.60
Equipment depreciation	$ 2,740	$ 0.55
Truck operating expenses	$ 5,730	$ 1.60
Rent	$ 4,680
Administrative expenses	$ 3,840	$ 0.60

For example, wages and salaries should be $21,300 plus $16.00 per repair-hour. The company expected to work 2,900 repair-hours in May, but actually worked 2,800 repair-hours. The company expects its sales to be $51.00 per repair-hour.