There are only 20 questions in an English test, 5 points will be awarded for each correct question, and 3 points will be deducted for each incorrect question (no miscalculation). Pippi failed the exam this time, but he found that as long as he made one less mistake, he could pass. How many questions did he get right?
一次英语考试只有20道题，做对一题加5分，做错一题倒扣3分(不做算错)．皮皮这次没考及格，不过他发现，只要他少错一道题就能及格．他做对了多少道题．
<gadget id="calculator">5 * 20</gadget>
<output>100</output>

<gadget id="calculator">100 - 52</gadget>
<output>48</output>

<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">48 / 8</gadget>
<output>6</output>

<gadget id="calculator">20 - 6</gadget>
<output>14</output>

<result>14</result>