Could I please have an explanation of the exercise?

Required information [The following information applies to the questions displayed below] Data for Hermann Corporation are shown below: Percent Per Unit of Sales Selling price $ 90 100% Variable expenses 63 70 Contribution margin $ 27 3096 Fixed expenses are $30,000 per month and the company is selling 2,000 units per month. Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $5,000 and monthly sales increase by $9,000? 1-b. Should the advertising budget be increased? Complete this question by entering your answers in the tabs below. Req 1A Req 13 How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $5,000 and monthly sales increase by $9,000? decreases X . . . Re 13 > Thls Is a numeric cell, so please enter numbers only. Complete this question by entering your answers in the tabs below. Req 1A Req 1B Should the advertising budget be increased? OYes No