Jake's Roof Repair has provided the following data concerning its costs: For example, wages and salaries should be $20,700 plus $16.00 per repair-hour. The company expected to work 3,000 repair-hours May, but actually worked 2,900 repair-hours. The company expects its sales to be $46.00 per repair-hour. Required: Compute the compary's activity variances for May. (indicate the effect of each variance by selecting "F" for favorable, " U " for unfavorable, and "None" for no effect (l.e., zero varlance). Input all amounts as positive values.)