Contribution Margin Willie Company sells 20,000 units at $25 per unit. Variable costs are $17.50 per unit, and fixed costs are $66,000. Determine (a) the contribution margin ratio, (b) the unit contribution margin, and (c) operating income. a. Contribution margin ratio (Enter as a whole number.) :] % b. Unit contribution margin (Round to the nearest cent.) 95:] per unit c. Operating income $:]