Exercise 6-5 Changes in Variable Costs, Fixed Costs, Selling Price, and Volume (L06-4) [The following information applies to the questions displayed below.) Data for Hermann Corporation are shown below: Selling price Variable expenses Contribution margin Per Unit $ 120 78 $ 42 Percent of Sales 100x 65 35% Fixed expenses are $84,000 per month and the company is selling 2,600 units per month. Exercise 6-5 Part 1 Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $8.900 and monthly sales increase by $18,000? 1-b. Should the advertising budget be increased