Whirly Corporations contribution format income statement for the most recent month is shown below:

Total Per Unit Sales (7,800 units) $ 234,000 $ 30.00 Variable expenses 156,000 20.00 Contribution margin 78,000 $ 10.00 Fixed expenses 55,900 Net operating income $ 22,100 Required: (Consider each case independently):

1. What would be the revised net operating income per month if the sales volume increases by 90 units?
2. What would be the revised net operating income per month if the sales volume decreases by 90 units?
3. What would be the revised net operating income per month if the sales volume is 6,800 units?