A manufacturer estimates that it will incur variable indirect costs for the month of October of $70,000 and $30,000 of fixed costs. The company uses direct labor hours to calculate the predetermined overhead rate and predicted that 3,000 direct labor hours would be used in October. Actual direct labor hours amounted to 3,200. Required: A) What is the variable predetermined indirect rate for October? B) What is the fixed predetermined indirect cost rate for October? C) What is the total allocation rate per direct labor hour for October? Arthur's Plumbing reported the following: RevenuesVariablemanufacturingcostsVariablenonmanufacturingcostsFixedmanufacturingcostsFixednonmanufacturingcosts$4,500$900$810$630$545 Required: a. Compute contribution margin. b. Compute contribution margin percentage. c. Compute gross margin. d. Compute gross margin percentage. e. Compute operating income