The company is currently selling 5,000 units per month. Fixed expenses are $243,000 per month. The marketing manager believes that an $11,000 increase in the monthly advertising budget would result in a 180 unit increase in monthly sales. What should be the overall effect on the company's monthly net operating income of this change?

Per Unit Percent of sales

selling prices $150 100%

variable exp 90 60%

cont margin 60 40%

a. increase of $200 b. decrease of $200 c. increase of $10,800 d. decrease of $11,000

• The answer is B, but I need to know how to solve this problem.