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: Check My Work Margin; Contribution Margin - (Fixed Manufacturing Costs + Fixed Selling and Administrative Expenses) = Operating income *Variable Cost of Goods Manufactured = Total Cost of Goods Manufactured - Fixed Manufacturing Cost **Variable Costing Ending Inventory = (Variable Cost of Goods Manufactured/Total Units of Goods Manufactured) x Absorption Costing Ending Inventory Units (given)