28 Ebay Manufacturing Company produces and sells one product. Information for this product appears below: Selling price Variable expenses Contribution margin Percent of Per Unit $280 126 $154 Sales 100% 45% 55% Ebay's total fixed expenses are $354,000 per month. Ebay's current monthly sales volume is 4,900. Required: Ebay's marketing manager believes that a $23,000 increase in monthly advertising expenditures would result in a 170 increase in monthly unit sales. How much would Ebay's monthly operating income change as a result of these expectations? Change in net operating income