Data for Hermann Corporation are shown below: Selling price Per Unit $ 60 Percent of Sales Variable expenses 39 100% 65 Contribution margin $ 21 35% 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. Reg 1A Req 18 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.) Not operating income by Red 1A Req 18 >