Could someone explain these?

Oslo Company prepared the following contribution format income statement based on a sales volume of 1,000 units (the relevant range of production is 500 units to 1,500 units): Sales Variable expenses Contribution margin Fixed expenses Net operating income $ 20,000 12,000 8,000 6,000 2,000 ta Foundational 6-13 13. Using the degree of operating leverage, what is the estimated percent increase in net operating income of a 5% increase in sales? Oslo Company prepared the following contribution format income statement based on a sales volume of 1,000 units (the relevant range of production is 500 units to 1,500 units): Sales Variable expenses Contribution margin Fixed expenses Net operating income $ 20,000 12,000 8,000 6,000 $ 2,000 Foundational 6-14 14. Assume that the amounts of the company's total variable expenses and total fixed expenses were reversed. In other words, assume that the total variable expenses are $6,000 and the total fixed expenses are $12,000. Under this scenario and assuming that total sales remain the same, what is the degree of operating leverage? Degree of operating leverage Oslo Company prepared the following contribution format income statement based on a sales volume of 1,000 units (the relevant range of production is 500 units to 1,500 units): Sales Variable expenses Contribution margin Fixed expenses Net operating income $ 20,000 12 , . 8,000 6,000 $ 2,000 Foundational 6-15 15. Assume that the amounts of the company's total variable expenses and total fixed expenses were reversed. In other words, assume that the total variable expenses are $6,000 and the total fixed expenses are $12,000. Given this scenario and assuming that total sales remain the same. Using the degree of calculated operating leverage, what is the estimated percent increase in net operating income of a 5% increase in sales? Increase in net operating income %