Required information [The following information applies to the questions displayed below. Data for Hermann Corporation are shown below: Percent of Sales 100% 60 Per Unit $135 81 $ 54 Selling price Variable expenses Contribution margin 40% Fixed expenses are $87,000 per month and the company is selling 2,900 units per month. Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $9,200 and monthly sales increase by $20,250? 1-b. Should the advertising budget be increased