keAssignment costing concept: Sullivan Equipment Company Variable Costing Income Statement For the Month Ended March 31 $424,200 $200,600 (28,900) 171,700 $252,500 111,100 Sales (10,100 units) Variable cost of goods sold: Variable cost of goods manufactured Inventory, March 31 (1,700 units) Total variable cost of goods sold Manufacturing margin Variable selling and administrative expenses