There are 22 boys in Class 51 of Experimental Primary School and how many girls are there. If one of them is selected, the probability of choosing a boy is (11/20).
实验小学五1班有男生22人，女生多少人，若从中任选一人，则选到男生的可能性是(11/20)．
<gadget id="calculator">11 / 20</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">22 / (11/20)</gadget>
<output>40</output>

<gadget id="calculator">40 - 22</gadget>
<output>18</output>

<result>18</result>