Stratford Company makes a product that sells for $15 per unit' Variable costs are $6 per unit, and fixed costs total $180,000 annually.

Assume again that the company sold 28,000 units last year. The president feels that it would be unwise to change the selling price' instead, he wants to increase the sales commission by $2 per unit. He thinks that this move, combined with some increase in advertising, would cause annual sales to double. By how much could advertising be increased with profits remaining unchanged?