Contribution Margin Sally Company sells 18,000 units at $30 per unit. Variable costs are $19.20 per unit, and fixed costs are $91,400. Determine (a) the contribution margin ratio, (b) the unit contribution margin, and (c) operating income. a. Contribution margin ratio (Enter as a whole number.) fill in the blank 1 % b. Unit contribution margin (Round to the nearest cent.) $fill in the blank 2 per unit c. Operating income $fill in the blank 3