A batch of vegetables shipped back from the vegetable market sells 30% on the first day, sells 20% more than the first day on the second day, and sells 30 kilograms more on the second day than the first day, how many kilograms of vegetables are shipped back from the vegetable market?
菜场运回一批菜，第一天卖30%，第二天卖的比第一天卖的多20%，第二天比第一天多卖30千克，菜场运回蔬菜多少千克？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">30 / (1/5) / (3/10)</gadget>
<output>500</output>

<result>500</result>