Shipmaster T. Corporation distributes a product that sells for $8 per unit. Variable expenses are $4 per unit, and fixed expenses total $20000 annually. Assume that the company sold 34900 units last year. The president wants to increase the sales commission by $0.6 per unit. She thinks that this move, combined with some increase in advertising, would double annual unit sales. Q.: By how much could advertising be increased with profits remaining unchanged? A: $