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 (5,300 units) $159,000 Cost of goods sold: Cost of goods manufactured (6,200 units) $130,200 Inventory, April 30 (900 units) (18,900) Total cost of goods sold Gross profit Selling and administrative expenses Operating income \begin{tabular}{c} $47,700(111,300) \\ (27,300) \\ \hline$20,400 \\ \hline \end{tabular} Joplin Company Variable Costing Income Statement For the Month Ended April 30 Variable cost of goods sold: Fixed costs