Naughty's weight is 30 kilograms, which is exactly (3/7) of father's weight. How much is father's weight in kilograms?
淘气的体重是30千克，正好是爸爸体重的(3/7)，爸爸的体重是多少千克？
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">30 / (3/7)</gadget>
<output>70</output>

<result>70</result>