一列快车以108km/h行驶,一列慢车以72km/h行驶.已知快车身长200m,慢车身长100m.若相向而行,则两车错车时间多长?quickly！
问题描述：
一列快车以108km/h行驶,一列慢车以72km/h行驶.已知快车身长200m,慢车身长100m.若相向而行,则两车错车时间多长?
quickly！
答
t=s/v=(100+200)m/(30+20)m/s
=300/50s
=6s
答
(200/1000+100/1000) ÷ (108+72)
=0.3 ÷ 180
=1/600 (h)
=6(秒)