at year end, dub's wind generator co. had a $40,000 debit balance in its manufacturing overhead control account. overhead is applied to products based on direct labor cost. Relevant account balance information at year-end follows: Work in process finished goods cost of goods inventory inventory sold direct material $20,000 $80,000 $120,000 direct labor 10,000 40,000 50,000 factory overhead 20,000 80,000 100,000 totals 50,000 200,000 270,000 a) what predetermined OH rate was used during the year