Whirly Corporation's contribution format income statement for the most recent month is shown below: Sales (8,900 units) Variable expenses Total $ 311,500 178,000 Contribution margin 133,500 Fixed expenses 55,100 Net operating income $ 78,400 Required: Per Unit $ 35.00 20.00 $ 15.00 (Consider each case independently): 1. What would be the revised net operating income per month if the sales volume increases by 40 units? 2. What would be the revised net operating income per month if the sales volume decreases by 40 units? 3. What would be the revised net operating income per month if the sales volume is 7,900 units?