The store bought a batch of badminton rackets at a price of 30 yuan each and sold them at a price of 40 yuan each. Yuan, how many badminton rackets are there in this batch?
商店以每副30元的价格购进一批羽毛球拍，又以每副40元的价格售出，当剩下80副时，除已收回购进这批球拍所用的钱以外，还赚了100元，这批羽毛球拍共有多少副？
<gadget id="calculator">80 * 40</gadget>
<output>3_200</output>

<gadget id="calculator">3_200 + 100</gadget>
<output>3_300</output>

<gadget id="calculator">40 - 30</gadget>
<output>10</output>

<gadget id="calculator">3_300 / 10</gadget>
<output>330</output>

<result>330</result>