Chen Danli participated in the mathematics competition, and she scored a total of 270 points. The scoring standard is: 20 points for each correct answer, and 6 points deducted for each incorrect answer. It is known that the number of correct questions she got is 3 times that of wrong ones, and she has done all the questions. How many questions are there in this set of test papers?
陈旦莉参加数学竞赛，她一共得了270分．评分的标准是：每做对一道得20分，每做错一道倒扣6分．已知她做对题的数量是做错题的3倍，并且所有的题她都做了，这套试卷共有多少道题．
<gadget id="calculator">3 * 20</gadget>
<output>60</output>

<gadget id="calculator">60 - 6</gadget>
<output>54</output>

<gadget id="calculator">270 / 54</gadget>
<output>5</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

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

<result>20</result>