need help figuring out net operating income will increase by ?

The Marketing Department has proposed increasing the West Division's monthly advertising by $26,000 based on the belief that it would increase that division's sales by 15%. Assuming these estimates are accurate, how much would the company's net operating income increase (decrease) if the proposal is implemented? (Do not round intermediate calculations.) Wingate Company, a wholesale distributor of electronic equipment, has been experiencing losses for some time, as shown by its most recent monthly contribution format income statement: In an effort to resolve the problem, the company would like to prepare an income statement segmented by division. Accordingly, the Accounting Department has developed the following information