Chaps & Saddles, a retailer of tack and Western apparel earns an average contribution margin of 40 percent on its sales volume. Recently, the advertising manager of a local country radio station offered to run numerous radio advertisements for Chaps & Saddles at a monthly cost of $2,400.

a.	Compute the amount by which the proposed radio advertising campaign must increase Chaps & Saddless monthly sales volume to pay for itself.