The sixth grade held a mathematics competition. There were 20 questions in the test paper. For each correct question, 5 points were awarded, and 2 points were deducted for each wrong answer. Xiao Wei received a total of 79 points. How many questions did she get right?
六年级举办数学竞赛，试卷共20道题，每做对1道题得5分，不做或做错1题扣2分，小薇共得79分，她做对几道题？
<gadget id="calculator">5 * 20</gadget>
<output>100</output>

<gadget id="calculator">100 - 79</gadget>
<output>21</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">21 / 7</gadget>
<output>3</output>

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

<result>17</result>