210 grams of soybean oil can be extracted from 500 grams of soybeans. According to this calculation, Aunt Wang's family ate 4.2 kilograms of soybean oil in September, which is equivalent to how many kilograms of soybeans they ate?
用500克黄豆可以榨出210克豆油．照这样计算，王大妈一家人9月份吃豆油4.2千克，相当于吃了黄豆多少千克？
<gadget id="calculator">210 / 500</gadget>
<output>21/50 = around 0.42</output>

<gadget id="calculator">4.2 / (21/50)</gadget>
<output>10</output>

<result>10</result>