在路程问题中,“遇离”问题变化较大,许多同学往往无从下手。能否恰当选取参照物来确定相等关系,是解此类问题的关键。例1 甲、乙两列火车的长分别为200米、280米,在双行的轨道上相向匀速而行,已知两车自车头相遇到车尾相离经过18秒,甲、乙两车的速度比为5:3,求两车的速度各是多少。 In the problem of distance, the problem of “victimism” has changed greatly, and many students are often unable to start. The key to solving such problems is whether or not the reference objects can be properly selected to determine the equivalence relationship. Example 1 The lengths of the two trains A and B are 200 meters and 280 meters, respectively, and they are moving at a uniform speed on the double-row track. It is known that the two cars face each other at the end of the car after 18 seconds, A and B vehicles. The speed ratio is 5:3. Find out how fast the two cars are.