Xiaohong used to have 10 more books than Xiaoying. Later, Xiaoying donated 5 books to "Hope Primary School", and Xiaohong bought 11 new books. At this time, Xiaohong's books are twice as many as Xiaoying's. How many books did they have in common?
小红原来比小英多10本书，后来小英捐了5本书给"希望小学"，而小红新买了11本书，这时小红的书比小英的书多2倍．原来两人共有多少本书．
<gadget id="calculator">10 + 11 + 5</gadget>
<output>26</output>

<gadget id="calculator">26 / 2</gadget>
<output>13</output>

<gadget id="calculator">13 + 5</gadget>
<output>18</output>

<gadget id="calculator">26 + 13</gadget>
<output>39</output>

<gadget id="calculator">39 - 11</gadget>
<output>28</output>

<gadget id="calculator">18 + 28</gadget>
<output>46</output>

<result>46</result>