Jake's Root Repair has provided the following data concerning its costs: For example, wages and salaries should be $21,200 plus $15.00 per repair-hour. The company expected to work 2,600 repairhours in May, but actually worked 2,500 repair-hours. The company expects its sales to be $52.00 per repair-hour- Compute the company's activity variances for May. (Indicate the effect of each variance by selecting "F" for favorable, "U" for Required: unfavorable, and "None" for no effect (i.e., zero variance). Input all amounts as positive values.)