There are 20 boys in a class, and the ratio of boys to girls is 10:11. How many girls are there in this class?
某班有男生20人，男、女生人数的比是10：11，这个班有女生多少人？
<gadget id="calculator">10 / 11</gadget>
<output>10/11 = around 0.909091</output>

<gadget id="calculator">20 / (10/11)</gadget>
<output>22</output>

<result>22</result>