Required information Exercise 5-5 (Algo) Changes in Variable Costs, Fixed Costs, Selling Price, and Volume [LO5-4] [The following information applies to the questions displayed below.] Data for Hermann Corporation are shown below: Per Unit Percent of Sales Selling price $ 60 Variable expenses 39 Contribution margin $ 21 100% 65 35% Fixed expenses are $72,000 per month and the company is selling 4,200 units per month. Exercise 5-5 (Algo) Part 1 Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $9,600, the monthly sales volume increases by 100 units, and the total monthly sales increase by $6,000? 1-b. Should the advertising budget be increased?