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 Required: a. What is the variable overhead rate variance for the month? b. What is the variable overhead efficiency variance for the month