There are 12 boys in the chorus, accounting for 3/10 of the chorus, so how many girls are there?
合唱队有男生12人，占到合唱队的(3/10)，那么女生有多少人．
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">12 / (3/10)</gadget>
<output>40</output>

<gadget id="calculator">40 - 12</gadget>
<output>28</output>

<result>28</result>