The following standards for variable overhead have been established for a company that makes only one product: Standard hours per unit of output 4.4 hours Standard variable overhead rate $16.00 per hour The following data pertain to operations for the last month: Actual hours 8, 100 hours Actual total variable overhead cost $124, 990 Actual output 1, 820 units a. What is the variable overhead rate variance for the month? (Input the amount as a positive value. Leave no cells blank - be certain to enter "0" wherever required. Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance.) Variable overhead rate variance b. What is the variable overhead efficiency variance for the month? (Input the amount as a positive value. Leave no cells blank - be certain to enter "0" wherever required. Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance.) Variable overhead efficiency variance