Need help in all! please add steps/work and an explanation of how to find the Contribution Margin! thank you.

Whirly Corporation's contribution format income statement for the most recent month is shown below: Sales (8,500 units) Variable expenses Contribution margin Fixed expenses Net operating income Total $ 297,500 170,000 127,500 54,400 $ 73,100 Per Unit $ 35.00 20.00 $ 15.00 Required: (Consider each case independently) 1 What would be the revised net operating income per month of 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 of the sales volume is 7,500 units? 1 Revised net operating income 2. Revised not operating income 3. Revised not operating income