数学题：AB两地的路程是550千米，甲乙两车从两地同时相对而行，行了4小时没相遇，还剩20％。已知甲车每小时行60千米，求乙车每小时行多少千米？

数学题解答：设乙车每小时行x千米。

60×4＋4x＝550×（1-20%）

240+4x=440

4x=200

x=50

答：乙车每小时行50千米。

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