Re: 各位師兄,想向你們請教兩條數學題 -- SFXC forum

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Subject: Re: 各位師兄,想向你們請教兩條數學題

Author:
4d boy

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Date Posted: 21:36:41 07/18/03 Fri
In reply to: 中四人 's message, "各位師兄,想向你們請教兩條數學題" on 12:59:33 07/18/03 Fri

>Q1
>Tom and Peter working together can load a truck in 2
>hours.If they work esparately,Tom requires 3 hours
>less than Peter to load a truck.Find the time Peter
>requires to load a truck alone.
let x be the time peter requires,
so that x-3 be the time tom requires
1/x-3 + 1/x = 1/2
.
.
.
x=6 or x=1 (rejected)

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Re: 各位師兄,想向你們請教兩條數學題

Author:
成吉思汗
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Date Posted: 22:41:55 07/18/03 Fri

兩條題目同屬一類
你可以把一件工程(即load a truck 或 fill up the tank)看做1(個unit).
或者你可以想像1 unit是指Tom and Peter或taps A and B 要走的路程.(即其距離)
這裏的「速率」(即完成一件工作的速率)便是距離除以時.間,1/x,where x is the time required for the job to finish.
其個別速率相加便是其合作的速率了

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