设：AB两地相距yKM,设甲到B地用时为x,甲的速度为a,乙的速度为b,
y/x=a,y=ax
(y-30)/a=b
乙到A地用时为(y+40)/a=y/b
用y=ax代入,得
(ax+40)/a=ax/(ax-30/a),解得；ax=120
所以y=ax=120 ,
即AB两地相距120KM.
数学应用题：（1）.
数学应用题：（1）.
1,甲,乙两车同时从A,B两地相向而行,当甲到达B地时,乙车距A地30km；当乙到大A地时,甲车超过B地40km.问A,B两地相距多少千米?
1,甲,乙两车同时从A,B两地相向而行,当甲到达B地时,乙车距A地30km；当乙到大A地时,甲车超过B地40km.问A,B两地相距多少千米?
数学人气：629 ℃时间：2020-05-20 20:09:18
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