Jakes Roof Repair has provided the following data concerning its costs: Fixed Cost per Month Cost per Repair-Hour Wages and salaries $ 21,100 $ 15.00 Parts and supplies $ 7.40 Equipment depreciation $ 2,790 $ 0.50 Truck operating expenses $ 5,780 $ 1.80 Rent $ 4,680 Administrative expenses $ 3,880 $ 0.70 For example, wages and salaries should be $21,100 plus $15.00 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 $48.00 per repair-hour. Required: Compute the companys activity variances for May. (Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance). Input all amounts as positive values.)