Second Chance LLC is a paperback book exchange. For each book trade, the buyer pays a $1 trade fee. Books that are sold and not traded cost half of their original purchase price. The store has total assets of $126,000 and current assets of $40,200. Its net sales equaled $35,000, and its net profit after taxes was $9,000. Calculate the store's net profit percentage.

7.1%

21.7%

22.4%

25.7%

27.7%