The following standards for variable overhead have been established for a company that makes only one product: Standard hours per unit of output: 4.5 hours Standard variable overhead rate: $16.00 per hour The following data pertain to operations for the last month: Actual hours: 8,200 hours Actual total variable overhead cost: $125,000 Actual output: 1,810 units What is the variable overhead rate variance for the month? (F or U) What is the variable overhead efficiency variance for the month? (F or U)