From the sale of sleeping bags, a retailer made a gross profit of 15% of the wholesale cost. If each sleeping bag was sold for $28, what was the wholesale cost per bag?
Choose the correct choice:
A) 3.0  B) 3.36  C) 24.34  D) 25.0  E) 31.36

Rationale: "cost price * 1.15 = selling price - - > cost price * 1.15 = $ 28 - - > cost price = $ 24.34 . answer : c ."
Answer: C