On October 31, the end of the first month of operations, Maryville Equipment Company prepared the following income statement, based on the variable costing concept: Maryville Equipment Company Variable Costing Income Statement For the Month Ended October 31 Line Item Description Amount Amount Sales (10,800 units) $691,200 Variable cost of goods sold: Variable cost of goods manufactured $348,400 Inventory, October 31 (2,600 units) (67,600) Total variable cost of goods sold (280,800) Manufacturing margin $410,400 Variable selling and administrative expenses (183,600) Contribution margin $226,800 Fixed costs: Fixed manufacturing costs $67,000 Fixed selling and administrative expenses 43,200 Total fixed costs (110,200) Operatin