Final answer:
The actual variable overhead cost is $50,470, the flexible-budget amount is $45,450, the variable overhead spending variance is $5,020 unfavorable, and the variable overhead efficiency variance is $4,040 unfavorable.
Step-by-step explanation:
The actual variable overhead cost can be calculated by multiplying the actual machine-hours by the variable overhead cost per machine-hour. In this case, the actual machine-hours are 9,800 hours and the variable overhead cost per machine-hour is $5.15. Therefore, the actual variable overhead cost is $5.15 x 9,800 = $50,470 (option C).
The flexible-budget amount can be determined by multiplying the budgeted production units by the variable overhead cost per machine-hour. In this case, the budgeted production units are 90,000 units and the variable overhead cost per machine-hour is $5.05. Therefore, the flexible-budget amount is $5.05 x 9,000 = $45,450 (option B).
The variable overhead spending variance measures the difference between the actual variable overhead cost and the flexible-budget amount. In this case, the actual variable overhead cost is $50,470 and the flexible-budget amount is $45,450. Therefore, the variable overhead spending variance is $50,470 - $45,450 = $5,020 unfavorable (option C).
The variable overhead efficiency variance measures the difference between the flexible-budget amount and the product of the actual machine-hours and the variable overhead cost per machine-hour. In this case, the flexible-budget amount is $45,450 and the product of the actual machine-hours and the variable overhead cost per machine-hour is ($5.05 x 9,800) = $49,490. Therefore, the variable overhead efficiency variance is $45,450 - $49,490 = $4,040 unfavorable (option A).