A tunnel is 2550 meters long. It takes 28 seconds for a train to pass through. The speed of the train is 100 meters per second. How long is the train in meters?
一个隧道长2550米，一列火车通过用了28秒，火车的速度是每秒100米，火车长多少米？
<gadget id="calculator">100 * 28</gadget>
<output>2_800</output>

<gadget id="calculator">2_800 - 2_550</gadget>
<output>250</output>

<result>250</result>