Number of visits 8,000 9,000 10,000 11,000 12,000 Revenue per visit $40 Total revenues $320,000 $360,000 $400,000 $440,000 $480,000 Variable cost per visit $6 Total variable costs 48,000 54,000 60,000 66,000 72,000 Contribution margin 272,000 306,000 340,000 374,000 408,000 Total fixed costs 257,500 257,000 257,500 257,500 257,500 Taxable Income $14,500 $48,500 $82,500 $116,500 $150,500 Taxes at 30% rate 4,350 14,550 24,750 34,950 45,150 Profit $10,150 $33,950 $57,750 $81,550 $105,350 Percentage change in volume from base case -20% -10% 0% 10% 20% Percentage change in profit from base case -82.4% -41.2% 0.0% 41.2% 82.4% Degree of operating leverage (DOL) at base case 4.12 Change in profit based on DOL -82.4% -41.2% 0.0% 41.2% 82.4% b.) DOL at 9,000 visits: 6.31