An express train and a slow train are running towards each other. The express train is 130 meters long and travels 21 meters per second. The slow train is 250 meters long and travels 17 meters per second.
一列快车和一列慢车相向而行，快车长130米，每秒行驶21米，慢车长250米，每秒行驶17米，两车从相遇到错开，需要多少秒．
<gadget id="calculator">130 + 250</gadget>
<output>380</output>

<gadget id="calculator">21 + 17</gadget>
<output>38</output>

<gadget id="calculator">380 / 38</gadget>
<output>10</output>

<result>10</result>