There are 20 questions in a mathematics competition. Regulations: 5 points are given for 1 question correctly, 4 points will be deducted for 1 wrong question, and no points will be given for questions that are not answered. Xiaohua has done all the questions in this competition, and the total score is 73 points. How many questions did she get right?
一次数学竞赛共20道题．规定：做对1题给5分，做错1题不给分外还倒扣4分，不做的题不给分．小花在这次竞赛中全部题都做了，总分是73分．她做对了几道题？
<gadget id="calculator">27 / 9</gadget>
<output>3</output>

<gadget id="calculator">20 - 3</gadget>
<output>17</output>

<result>17</result>