单选题 On a purchase of $120， a store offered a payment plan consisting of a $20 down payment and 12 monthly payments of $10 each. What percent of the purchase price， to the nearest tenth of a percent, did the customer pay in interest by using this plan?

【正确答案】 A
【答案解析】[解析] 消费者总共付的钱为20+12×10=140美元，所以其所付的利息为140-120=20美元，因此利息占商品价格的百分数为：20÷120=16.7%。