There are 15 questions in the mathematics competition. It is stipulated that 8 points will be awarded for each correct question, and 4 points will be deducted for each wrong answer. Xiaohua scored 72 points in total for all the questions. So how many questions did he get right?
数学竞赛题共15道，规定每做对一题得8分，每做错一题倒扣4分，不做的不给也不扣．小华各题均做共得72分．那么他做对了多少道题．
<gadget id="calculator">8 * 15</gadget>
<output>120</output>

<gadget id="calculator">120 - 72</gadget>
<output>48</output>

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

<gadget id="calculator">48 / 12</gadget>
<output>4</output>

<gadget id="calculator">15 - 4</gadget>
<output>11</output>

<result>11</result>