A train is 200 meters long. It takes 2 minutes to pass a bridge at a speed of 30 kilometers per hour. How long is the bridge in meters?
一列火车长200米，它以每小时30千米的速度通过一座桥，用了2分钟时间，这座桥全长多少米？
<gadget id="calculator">500 * 2</gadget>
<output>1_000</output>

<gadget id="calculator">1_000 - 200</gadget>
<output>800</output>

<result>800</result>