Exercise 6-1 The Effect of Changes in Activity on Net Operating Income [LO6-1] Whirly Corporation's contribution format income statement for the most recent month is shown below: Required: (Consider each case independently): 1. What would be the revised net operating income per month if the sales volume increases by 60 units? 2. What would be the revised net operating income per month if the sales volume decreases by 60 units? 3. What would be the revised net operating income per month if the sales volume is 7,300 units? Exercise 6-4 Computing and Using the CM Ratio [LO6-3] Last month when Holiday Creations, Inc., sold 40,000 units, total sales were $311,000, total variable expenses were $227,030, and fixed expenses were $36,300, Required: 1. What is the company's contribution margin (CM) ratio? 2. What is the estimated change in the company's net operating income if it can increase total sales by $2,900 ? (Do not round intermediate calculations.)