RPM manufactures racks for CDs. Costs are $12.70 per rack. A wholesaler buys CD racks from RPM at $18.70 each, then sells them at $35.20 to retailers. The retailer sells the racks for $55.70 each to consumers. How much more unit contribution does the retailer earn using margin instead of markup per sale?

CALCULATED VARIABLES: rpmark = $41.31 rpmarg = $47.78 rmarpct = 0.368 (36.8%) margin = $20.50