Xiaoying participated in the class intelligence competition. The rule is: 10 points for 1 correct answer, 5 points deducted for 1 wrong answer, she answered 10 questions quickly, and the final score is 70 points, how many questions Xiaoying answered correctly.
小英参加班级智力抢答比赛．规则是：答对1题得10分，答错1题倒扣5分，她抢答了10题，最后得分是70分，小英答对了多少道题．
<gadget id="calculator">10 * 10</gadget>
<output>100</output>

<gadget id="calculator">100 - 70</gadget>
<output>30</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">30 / 15</gadget>
<output>2</output>

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

<result>8</result>