Jake's Roof Repair provided the following data concerning its costs: For example, wages and salaries should be $21,500 plus $16.00 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 $54.00 per repair-hour. Required: Compute the company's activity variances for May. Note: 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