The number of boys in a class is 40% of the number of girls, and the number of girls is equal to the number of boys.
某班男生是女生的40%，女生人数是男生人数的多少．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 * (2/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / (2/5)</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>