Feather Friends, Inc., distributes a high-quality wooden birdhouse that sells for $20 per unit. Variable expenses are $8 per unit, and fixed expenses total $180,000 per year. Its operating results for last year were as follows: Sales $400,000 Variable expenses 160,000 Contribution margin 240,000 Fixed expenses 180,000 Net operating income $60,000 Required: 1. If this year's sales increase by $75,000 and fixed expenses do not change, how much will net operating income increase? 2. What is the degree of operating leverage based on last year's sales? Assume the president expects this year's sales to increase by 20%. Using the degree of operating leverage from last year, what percentage increase in net operating income will the company realize this year?3. The president does not want to change the selling price. Instead, he wants to increase the sales commission by $1 per unit. He thinks that this move, combined with some increase in advertising, would increase this year's sales by 25%. How much could the president increase this year's advertising expense and still earn the same $60,000 net operating income as last year?