The clothing store sold 17 pieces of the same tops in the morning and 21 pieces in the afternoon, earning 460 yuan more in the afternoon than in the morning. How much is each top?
服装店上午卖出同样的上衣17件，下午卖出21件，下午比上午多收入460元．每件上衣多少钱？
<gadget id="calculator">21 - 17</gadget>
<output>4</output>

<gadget id="calculator">640 / 4</gadget>
<output>160</output>

<result>160</result>