Donaldson Company's contribution format income statement for the most recent month is shown below: Sales Variable expenses Contribution margin Fixed expenses Net operating income Total $500,000 Per Unit $12.50 300,000 7.50 200,000 $ 5.00 180,000 $ 20,000 The company sold 40,000 units in its most recent month and its relevant range of production is 30,000 to 50,000 units.