Students in class 6 and 1 do three exercises. Among them, (1/4) students make 1 mistake, (1/6) students make 2 mistakes, and (1/9) students make 3 mistakes. If there are no more than 50 students in the class, how many students can answer all the questions correctly?
六1班同学做三道练习题．其中(1/4)的学生错1道，(1/6)学生错2道，(1/9)的学生错3道．若全班学生不超过50人，那么全部答对的学生有多少人．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 - (1/4) - (1/6) - (1/9)</gadget>
<output>17/36 = around 0.472222</output>

<gadget id="calculator">36 * (17/36)</gadget>
<output>17</output>

<result>17</result>