Jake's Roof Repair has provided the following data concerning its costs: Fixed Cost per Month $ 21,300 Wages and salaries Parts and supplies Equipment depreciation Truck operating expenses Rent Administrative expenses Cost per Repair-Hour $ 15.00 $ 7.60 $ 0.50 $ 1.80 $ 2,710 $ 5,750 $ 4,630 $ 3,870 $ 0.60 For example, wages and salaries should be $21,300 plus $15.00 per repair-hour. The company expected to work 3,000 repair-hours in May, but actually worked 2,900 repair-hours. The company expects its sales to be $52.00 per repair-hour. Required: Compute the company's 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.)