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-   -   The Train Puzzle (https://www.mersenneforum.org/showthread.php?t=7688)

Eivind 2007-04-04 09:16

[CODE]At time 0 a freight train meets up with the first man.
It overtakes the first man in 20 seconds.
10 minutes later it meets the second man coming the other way.
[/CODE]

I would interpretate this as the train meets the second man at time 10min 20sec.

Is the english language ambiguous about which sentence "later" referes to?

-Eivind

davieddy 2007-04-04 11:00

[quote=Eivind;102966]
I would interpretate this as the train meets the second man at time 10min 20sec.

Is the english language ambiguous about which sentence "later" referes to?

-Eivind[/quote]

That's how we interpreted it.
But having set up this way of allocating a time to each event,
the setter of the problem abandoned it.

I initially thought he meant that the train met the second man
at time 10 minutes, and meant to ask "at what time do the men meet?"

David

davieddy 2007-04-04 14:15

[quote=cheesehead;102941]Oh, okay. That's why I was trying specific numbers for speed and length.[/quote]

If the answer depended on these, they would be specified in the question.
It doesn't, (wherein lies the attractiveness of the problem).
But from your convoluted (mis)calculation, this may not be
immediately apparent:smile:

David

petrw1 2007-04-04 17:22

Let me be more specific....
 
Two men (A and B) are walking toward each other along a railway track as in the amazingly lifelike :smile: picture below.
A is walking EAST; B is walking WEST
(W) === A--> ============================= <--B === (E)
At time 0 a freight train meets up with the first man.
=== The train is also heading EAST.
=== At time 0 the FRONT of the train is even with man A
It overtakes the first man in 20 seconds.
=== At time 20 seconds the BACK of the train is even with man A
10 minutes later it meets the second man coming the other way.
=== At time 10:20 the FRONT is the train meets man B
The train passes the second man in 18 seconds.
=== At time 10:38 the END of the train leaves man B
How long after the train has passed him will the two men meet??
=== How long after time 10:38, that is
Assume constant speeds throughout.
However, do NOT assume both men are walking the same speed.

davieddy 2007-04-04 18:36

Yes. We all guessed that.

cheesehead 2007-04-05 07:16

[quote=davieddy;102984]If the answer depended on these, they would be specified in the question.
It doesn't, (wherein lies the attractiveness of the problem).[/quote]What I meant was that I was trying specific numbers to see whether I was interpreting the problem wording correctly.


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