The following costs result from the production and sale of 4,950 drum sets manufactured by Tight Drums Company for the year ended December 31, 2017. The drum sets sell for $345 each. The company has a 40% income tax rate. Variable production costs Plastic for casing $ 178,200 Wages of assembly workers 499,950 Drum stands 222,750 Variable selling costs Sales commissions 168,300 Fixed manufacturing costs Taxes on factory 5,500 Factory maintenance 11,000 Factory machinery depreciation 71,000 Fixed selling and administrative costs Lease of equipment for sales staff 11,000 Accounting staff salaries 61,000 Administrative management salaries 141,000 Required: 1. Prepare a contribution margin income statement for the company. 2. Compute its contribution margin per unit and its contribution margin ratio.