Wang Fang participated in the TV quiz contest. She got 8 points for each correct answer and 4 points for each wrong answer. Wang Fang answered 20 questions and got 100 points. How many questions did she answer correctly?
王芳参加电视抢答赛，每答对一题得8分，答错一题扣4分，王芳抢答了20道题，得了100分，她答对了几题？
<gadget id="calculator">20 * 8</gadget>
<output>160</output>

<gadget id="calculator">160 - 100</gadget>
<output>60</output>

<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<gadget id="calculator">60 / 12</gadget>
<output>5</output>

<gadget id="calculator">20 - 5</gadget>
<output>15</output>

<result>15</result>