Contribution Margin and Contribution Margin Ratio For a recent year, McDooley's, a family-owned group of restaurants, had the following sales and expenses: Assume that the variable costs consist of food and paper, payroll and employee benefits, and 40% of the selling, general, and administrative expenses. a. What is McDooley's contribution margin? \$ b. What is McDooley's contribution margin ratio? Round your percentage answer to one decimal place. % c. How much would operating income increase if the stores sales increased by $7,800 for the coming year, with no change in the contribution margin ratio or fixed costs? 13 d. What would have been the operating income or loss for the recent year if sales had been $7,800 more