Required information [The following information applies to the questions displayed below.) Data for Hermann Corporation are shown below: Selling price Variable expenses Contribution margin Percent Per Unit of Sales $ 60 1008 39 $21 65 359 Fixed expenses are $72,000 per month and the company is selling 4,200 units per month. 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? Complete this question by entering your answers in the tabs below. Req 1A Req 1B 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? (Do not round intermediate calculations.) Net operating income by