Sales (21,000 units) Variable expenses Contribution margin Fixed expenses $ 126,000 h 75,600 Total Per Unit $ 6.00 3.60 50,400 $ 2.40 29,400 Net operating income $ 21,000 Required: (Consider each of the four requirements independently): 1. Assume the sales volume increases by 3,570 units: a. What is the revised net operating income? b. What is the percent increase in unit sales? c. Using the most recent month's degree of operating leverage, what is the percent increase in net operating income? 2. What is the revised net operating income if the selling price decreases by $1.30 per unit and the number of units sold increases by 18%? 3. What is the revised net operating income if the selling price increases by $1.30 per unit, fixed expenses increase by $8,000, and the number of units sold decreases by 8%? 4. What is the revised net operating income if the selling price per unit increases by 10%, variable expenses increase by 30 cents per unit, and the number of units sold decreases by 10%?