Freytag Corporation's variable overhead is applied on the basis of direct labor-hours. The company has established the following variable overhead standards for product N06C: Standard direct labor-hours 5.5 hours per unit of N06C Standard variable overhead rate $ 4.10 per hour The following data pertain to the most recent month's operations during which 1,600 units of product N06C were made: Actual direct labor-hours worked 8,700 Actual variable overhead incurred $ 36,540 Required: a. What was the variable overhead rate variance for the month? b. What was the variable overhead efficiency variance for the month?