Problem 5-1A Contribution margin income statement and contribution margin ratio LO A1 The following costs result from the production and sale of 4,650 drum sets manufactured by Tight Drums Company for the year ended December 31, 2017. The drum sets sell for $315 each. The company has a 30% income tax rate Variable production costs Plastic for casing Wages of assembly workers $ 139,589 441,750 181,350 Drum stands Variable selling costs Sales commissions 130,280 Fixed manufacturing costs Taxes on factory Factory maintenance Factory machinery depreciation 8,500 17,000 77,800 Fixed selling and administrative costs Lease of equipment for sales staff Accounting staff salaries Administrative management salaries 17,000 67,000 147,000 Required 1. Prepare a contribution margin income statement for the company 2. Compute its contribution margin per unit and its contribution margin ratio