一道数学题``````````````````````````````````````````````````````````

来源:百度知道 编辑:UC知道 时间:2024/05/07 08:17:13
一辆货车从甲地开往乙地,行完全程要8小时,一辆客车以每小时54千米的速度同时从乙地开往甲地,行了全程的十二分之五后,正好与货车相遇,这时客车行了多少千米?

(1-5/12)÷1/8 ×54=252(km)

设货车车速为xkm/h,甲乙两地距离为Skm,客车和货车相遇用了t小时。
一辆货车从甲地开往乙地,行完全程要8小时:S=8x
一辆客车以每小时54千米的速度同时从乙地开往甲地,行了全程的十二分之五后,正好与货车相遇:S=tx+54t,54t=5S/12
tx=7S/12
∵S=8x
∴tx=14x/3
∵x≠0
∴t=14/3
S客车=54t=252