The number of boys in the art group of Xinghe Primary School accounts for (2/5) of the total number. There are 21 known girls, how many boys are there?
星河小学美术组男生人数占总人数的(2/5)．已知女生有21人，男生有多少人？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">21 / (3/5)</gadget>
<output>35</output>

<gadget id="calculator">35 * (2/5)</gadget>
<output>14</output>

<result>14</result>