Would you please explain how to get the correct answer?

A company's marketing manager is considering a plan to increase his annual advertising budget by $180,000. By doing so, he estimates that the company's annual revenue would increase by $400,000 over its current level. The company's contribution margin ratio is 40%. If the marketing manager's plan is implemented, the company's operating income is expected to decrease by $ 72000 Blank 1 Correct Answer Blank 1: 20,000