The store bought a batch of volleyballs at a price of 6 yuan each, and sold them at 8 yuan. When the remaining 10 were sold, the profit was 200 yuan in addition to the cost. How many volleyballs are there in this batch?
商店以每只6元的价钱买进一批排球，售价为8元，卖到剩下10只时，除成本外还获利润200元，这批排球有几只？
<gadget id="calculator">8 * 10</gadget>
<output>80</output>

<gadget id="calculator">80 + 200</gadget>
<output>280</output>

<gadget id="calculator">8 - 6</gadget>
<output>2</output>

<gadget id="calculator">280 / 2</gadget>
<output>140</output>

<result>140</result>