In a mathematics competition, there are two ways to give points: one is to give 5 points for a correct answer, 2 points for no answer, and no points for a wrong answer; the other is to give 40 points first, and 3 points for a correct answer, and no answer No points will be given, and 1 point will be deducted for wrong answers. Using these two methods of scoring, a certain examinee gets 81 points. How many questions are there in this test paper?
一次数学比赛，有两种给分方法：一种是答对一题给5分，不答给2分，答错不给分；另一种先给40分，答对一题给3分，不答不给分，答错扣1分．用这两种方法评分，某考生都得81分，这张试卷共有多少题？
<gadget id="calculator">15 + 3 + 4</gadget>
<output>22</output>

<result>22</result>