tunnel is 4500m long. A train passes through the tunnel at a speed of 1200m per minute. It takes 4 minutes from the front of the train entering the tunnel to the end of the train leaving the tunnel. How long is the train in meters? (column equation solution)
一条隧道长4500m，一列火车以每分钟1200m的速度穿过隧道，从车头进入隧道到车尾离开隧道共需要4分钟，这列火车长多少米？(列方程解答)
<gadget id="calculator">1_200 * 4</gadget>
<output>4_800</output>

<gadget id="calculator">4_800 - 4_500</gadget>
<output>300</output>

<result>300</result>