The attached screenshot is the question, please provide detailed calculation and explanation, thank you!!

Question 4. ( 8 marks ) Martinez Building Products Company is one of the largest manufacturers and marketers of unique , custom made residential garage doors in the U. S. It also is a major supplier of industrial and commercial doors , grills , and counter shutters for the new construction , repair , and remodel markets . Martinez uses a job cost system and applies overhead to production on the basis of direct labour cost . In computing a predetermined overhead rate for the year 2018 , the company estimated manufacturing overhead to be $24 million and direct labour costs to be $20 million . In addition , it developed the following information . Actual costs incurred during 2018 Direct materials used $30, 000, 000 Direct labour cost incurred 21, 000, 000 Insurance for factory 500, 000 Indirect labour 7, 500, 000 Factory maintenance* 1 , 000 , 000 Rent on factory building* 11 ,000 , 000 Depreciation on factory equipment 2, 000 , 000 Required 1 ) Why is Martinez Building Products Company using a job costing system ? ( 3 marks ) 2 ) On what basis does Martinez allocate it's manufacturing overhead ? Please calculate* the predetermined overhead rate for 2018 . (3 marks ) 3 ) Calculate the amount of the under - or overapplied overhead for 2018 . ( 2 marks )