The manager for the sporting goods department planned to purchase $8,400 worth of merchandise at cost. This merchandise was to retail at $14,000. At Supplier A he purchased $4,340 at cost, with a retail value of $7,000. At Supplier B he purchased $3,720 at cost, with a retail value of $6,300. What markup percentage must the buyer take on purchases from a third supplier, C, to meet the overall markup objective.