2: Job-Order Costing: Calculating unit product costs Custom Corporation uses a job-order costing system with a single plantwide predetermined overhead rate based on machine-hours. The company based its predetermined overhead rate for the current year on the following data: Total machine-hours Total fixed manufacturing overhead cost Variable manufacturing overhead per machine-hour 20,000 $80,000 $3.00 Recently Job G215 was completed with the following characteristics: Number of units in the job Total machine-hours Direct materials Direct labor cost 40 70 $910 $3,600 Required: a. Estimate the total manufacturing overhead cost. (3 marks) b. Calculate the predetermined overhead rate for the year. (2 marks) c. Calculate the amount of overhead applied to Job G215. ( 2 marks) d. Calculate the total job cost for Job G215. (3 marks) e. Calculate the unit product cost for Job G215. (2 marks) f. Why do most companies use predetermined overhead rates rather than actual overhead rates