Teacher Li corrected 13 essays yesterday, the number of essays corrected today is twice as much as yesterday, and there are still 11 essays left to be corrected. So how many people are there in the class taught by Mr. Li?
李老师昨天批改了13篇作文，今天批改的篇数是昨天的2倍，结果还剩11本没批改．那么李老师所教的这个班共有多少人？
<gadget id="calculator">13 * 2</gadget>
<output>26</output>

<gadget id="calculator">13 + 26 + 11</gadget>
<output>50</output>

<result>50</result>