In a box there are red, yellow, and blue balls, which are identical except for their colours. Among them, there are 10 red balls, which are more than the number of yellow balls (1/4), and less than the number of blue balls (1/11). At least how many small balls can be drawn at a time to ensure that there are three different colors in the drawn balls.
在一个盒子里装有红、黄、兰三种颜色的小球，小球除颜色外完全形同．其中红色的小球共有10个，比黄色小球的个数多(1/4)，比蓝色小球的个数少(1/11)．一次至少摸出多少个小球才能保证摸出的球中有三种不同颜色．
<gadget id="calculator">1 / 11</gadget>
<output>1/11 = around 0.090909</output>

<gadget id="calculator">1 - (1/11)</gadget>
<output>10/11 = around 0.909091</output>

<gadget id="calculator">10 / (10/11)</gadget>
<output>11</output>

<gadget id="calculator">11 + 10 + 1</gadget>
<output>22</output>

<result>22</result>