Check my work R&R Tax Service offers tax and consulting services to individuals and small businesses. Data for fees and costs for three types of tax returns follow. Fixed costs total $98,000. Variable Cost Type of Return Easy Moderate Sales Mix Fee Charged per Return 20% $ 80 $ 50 10% 190 Business 70% 460 110 280 (1) Determine the weighted-average contribution margin. Easy Moderate Business Sales mix Contribution margin per return Total per unit 20% 10% 70% Weighted-average contribution margin