An express train with a body length of 800 meters, catches up with a slow train with a length of 1200 meters, the express train advances 500 meters per minute, and the slow train advances 300 meters per minute. minute?
一列快车车身长800米，追上一列车身长1200米的慢车，快车每分钟前进500米，慢车每分钟前进300米，从快车车头追上慢车车尾到快车车尾超过慢车车头，至少需要几分钟？
<gadget id="calculator">800 + 1_200</gadget>
<output>2_000</output>

<gadget id="calculator">500 - 300</gadget>
<output>200</output>

<gadget id="calculator">2_000 / 200</gadget>
<output>10</output>

<result>10</result>