Having some trouble with this problem. My calculations are not correct.

Variable Costing Income Statement 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 (6,600 units) $165,000 Cost of goods sold: Cost of goods manufactured (7,500 units) $135,000 Inventory, April 30 (1,100 units) (19,800) Total cost of goods sold (115,200) Gross profit $49,800 Selling and administrative expenses (30,130) Operating income $19,670 If the fixed manufacturing costs were $36,450 and the fixed selling and administrative expenses were $14,760, 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 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 Total fixed costs Operating income