3. Rhett Company has two departments, Machining and Assembly. The following estimates are for the coming year: Machining Assembly Direct labor hours 10,000 50,000 Machine hours 40,000 20,000 Manufacturing overhead $200,000 $400,000 A single predetermined overhead rate based on direct labor hours for the entire plant is a. $ 8 per direct labor-hour. b. $10 per direct labor-hour. c. $20 per direct labor-hour. d. none of the above