A shopping mall buys a batch of clothes. The purchase price of each set of clothes is 240 yuan, and the selling price is 272 yuan. After the sale, the total profit is 640 yuan. How many sets of clothes are there in this batch?
某商场购进一批服装，每套服装的进价是240元，售价是272元，售完后共赢利640元．这批服装有多少套？
<gadget id="calculator">272 - 240</gadget>
<output>32</output>

<gadget id="calculator">640 / 32</gadget>
<output>20</output>

<result>20</result>