In a math test, it was stipulated that 5 points would be awarded for a correct answer, and 5 points would be deducted for a wrong answer. A representative team composed of three students from the third grade answered 10 questions and scored a total of 30 points. How many questions were answered correctly?
一次数学测验中规定：做对一题得5分，答错一题倒扣5分，三年级3名同学组成的代表队抢答了10题，一共得了30分，问答对了多少题？
<gadget id="calculator">5 * 10</gadget>
<output>50</output>

<gadget id="calculator">50 - 30</gadget>
<output>20</output>

<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<result>8</result>