In the ecological farm, 60% of a batch of vegetables were sold on the first day, and 100kg on the second day. At this time, the ratio of the sold to the remaining was 7:3. How many kg were sold on the first day.
生态农场有一批菜第一天卖出60%，第二天卖出100kg，这时卖出的与剩下比7：3．第一天卖出了多少kg．
<gadget id="calculator">3 * 100</gadget>
<output>300</output>

<gadget id="calculator">7 * 100</gadget>
<output>700</output>

<gadget id="calculator">300 + 700</gadget>
<output>1_000</output>

<gadget id="calculator">7 * 0.4</gadget>
<output>2.8</output>

<gadget id="calculator">3 * 0.6</gadget>
<output>1.8</output>

<gadget id="calculator">2.8 - 1.8</gadget>
<output>1</output>

<gadget id="calculator">1_000 / 1</gadget>
<output>1_000</output>

<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1_000 * (3/5)</gadget>
<output>600</output>

<result>600</result>