Pls help, question 1a (the answer is not 1300). Managerial accounting.

Required information [The following information applies to the questions displayed below.] Data for Hermann Corporation are shown below: Selling price Variable expenses Contribution margin Per Unit $ 130 78 Percent of Sales 100% 60 $ 52 40% Fixed expenses are $86,000 per month and the company is selling 2,800 units per month. Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $9,100 and monthly sales increase by $19,500? 1-b. Should the advertising budget be increased? Complete this question by entering your answers in the tabs below