There is a 1000-meter-long steel bridge,and it takes the train 120reconds to get itd locomotive to the bridge and the rear rnd off it.Theduration of the whole train running on the bridge is 80sconds,what are the length and the speed of train? 一座铁桥长1000米,一列火车从车头上桥到车尾离开桥共用了120秒,已知整个火车完全在桥上行驶的时间为80秒,求火车的长度与火车的速度.