The math competition stipulates: There are 10 questions in total, 15 points for a correct answer, and 10 points for a wrong answer. Xiao Ming has completed all the questions and scored 100 points. How many questions did he answer correctly?
数学比赛中规定：总共有10题，答对一题得15分，答错一题扣10分，小明做完了所有的题，得了100分，他答对了几题？
<gadget id="calculator">15 * 10</gadget>
<output>150</output>

<gadget id="calculator">150 - 100</gadget>
<output>50</output>

<gadget id="calculator">15 + 10</gadget>
<output>25</output>

<gadget id="calculator">50 / 25</gadget>
<output>2</output>

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

<result>8</result>