4) Maximoff used as job order costing system. In the Mixing Department, overhead is applied using machine hours while the Paving Department uses direct labor hour. For the upcoming year, the company estimated the following data for its two departments: Direct labor hours Machine hours Total budgeted overhead cost Mixing Paving 12,000 28,000 60,000 $480,000 12,000 $700,000 Job #220 was started and completed. The job cost data is as follows: Direct material Direct labor cost Direct labor hours Machine hours Mixing $22,600 Paving $3,400 $1,250 $4,050 24 340 290 44 a) Compute the plantwide overhead rate using direct labor hours as the allocation base. What is the total cost of Job #220 if this plantwide rate is used? (10 points) b) Compute the plantwide overhead rate using machine hours as the allocation base. What is the total cost of Job #220 if this plantwide rate is used? (10 points) c) Compute the predetermined overhead rates using departmental rates. What is the total cost of Job #220 if departmental rates are used? (10 points) d) Which method is best: a) or b) or c). Why? (5 points)