sales (7,400 units) $ 229,400 $ 31.00 variable expenses 140,600 19.00 contribution margin 88,800 $ 12.00 fixed expenses 54,300 net operating income $ 34,500 required: (consider each case independently): 1. what would be the revised net operating income per month if the sales volume increases by 50 units? 2. what would be the revised net operating income per month if the sales volume decreases by 50 units? 3. what would be the revised net operating income per month if the sales volume is 6,400 units?