Final answer:
The variable overhead rate variances for lubricants and supplies can be calculated using certain formulas. The variances are then determined to be favorable or unfavorable.
Step-by-step explanation:
The variable overhead rate variances for lubricants and supplies can be calculated using the following formulas:
Lubricants variance = (Actual lubricants cost - Standard lubricants cost) / Actual machine-hours
Supplies variance = (Actual supplies cost - Standard supplies cost) / Actual machine-hours
Using the given data, the lubricants variance can be calculated as follows: (actual lubricants cost - (standard lubricants rate * actual machine-hours)) / actual machine-hours. The supplies variance can be calculated in a similar manner.
Based on the calculations, determine whether the variances are favorable (F) or unfavorable (U).