A 150-meter-long train passes a 250-meter-long bridge at a speed of 50 meters per second. How many seconds does it take from the front of the train to the bridge and the rear of the train to leave the bridge?
一列150米长的火车，以50米每秒的速度经过一座250米长的大桥，从车头上桥到车尾离桥，一共用了多少秒．
<gadget id="calculator">150 + 250</gadget>
<output>400</output>

<gadget id="calculator">400 / 50</gadget>
<output>8</output>

<result>8</result>