Sales (28,200 units) $ 169,200 $ 6.00 Variable expenses 101,520 3.60 Contribution margin 67,680 $ 2.40 Fixed expenses 39,480 Net operating income $ 28,200 Required: (Consider each of the four requirements independently): Assume the sales volume increases by 4,512 units: What is the revised net operating income? What is the percent increase in unit sales? Using the most recent months degree of operating leverage, what is the percent increase in net operating income? What is the revised net operating income if the selling price decreases by $1.40 per unit and the number of units sold increases by 23%? What is the revised net operating income if the selling price increases by $1.40 per unit, fixed expenses increase by $6,000, and the number of units sold