On April 30, the end of the first month of operations, Joplin Company prepared the following income statement, based on the absorption costing concept: Joplin Company Absorption Costing Income Statement For the Month Ended April 30 Sales (3,600 units) $111,600 Cost of goods sold: Cost of goods manufactured (4,200 units) $92,400 Inventory, April 30 (600 units) (13,200) Total cost of goods sold (79,200) Gross profit $32,400 Selling and administrative expenses (18,860) Operating income $13,540 If the fixed manufacturing costs were $21,252 and the fixed selling and administrative expenses were $9,240, prepare an income statement according to the variable costing concept. Round all final answers to whole dollars. Joplin Company Variable Costing Income Statement For the Month Ended April 30 Sales $ 111,600 Variable cost of goods sold: Variable cost of goods manufactured Inventory, April 30 Total variable cost of goods sold Manufacturing margin to Variable selling and administrative expenses Contribution margin Fixed costs: Fixed manufacturing costs $ 21,252 Variable selling and administrative expenses 9,240 Total fixed costs 30,492 Operating income