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 (3,800 units) $144,400 Cost of goods sold: Cost of goods manufactured (4,300 units) $116,100 Inventory, April 30 ( 600 units) (16,200) Total cost of goods sold Gross profit Selling and administrative expenses Operating income \begin{tabular}{l} (99,900) \\ \hline$44,500 \\ (25,870) \\ \hline$18,630 \\ \hline \hline \end{tabular} Joplin Company Variable Costing Income Statement For the Month Ended April 30 Sales Variable cost of goods sold: Variable cost of goods manufactured Inventory, April 30 Total variable cost of goods sold Manufacturing margin Variable selling and administrative expenses Contribution margin Fixed costs: Fixed manufacturing costs Fixed selling and administrative expenses Operating income Total fixed costs 7 $