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        riddles >> easy >> Trains and distances
        
(Message started by: EZ_Lonny on Dec 21^st, 2004, 8:00am)

Title: Trains and distances
Post by EZ_Lonny on Dec 21^st, 2004, 8:00am

Two trains are travelling on the same trace in opposite directions.

Say Train A departs from Place X towards Place Y with a speed of 200 mph.

Train B departs from Place Y towards Place X with a speed of 150 mph.

The distance between Place X and Place Y is 1050 miles.

At a certain moment they meet on that trace.

Question: What train is the furthest away from Place Y at that very moment?

Title: Re: Trains and distances
Post by THUDandBLUNDER on Dec 21^st, 2004, 8:41am

Quote:

Question: What train is the furthest away from Place Y at that very moment?

The one that is nearer to Place X.

Title: Re: Trains and distances
Post by John_Gaughan on Dec 21^st, 2004, 12:32pm

The third train that ran out of diesel at Place X.

Title: Re: Trains and distances
Post by WombatDeath on Dec 21^st, 2004, 2:18pm

Assuming that they don't leave the track when they collide, train [hide]A[/hide] will be furthest away.

Title: Re: Trains and distances
Post by Grimbal on Dec 22^nd, 2004, 1:48am

But it is still possible that the rails are winding so much that at the place of the collision train A is closer to Y than B.

Title: Re: Trains and distances
Post by EZ_Lonny on Dec 27^th, 2004, 5:04am

Did I say: same rails?

Title: Re: Trains and distances
Post by John_Gaughan on Dec 30^th, 2004, 6:05am

You said "same trace," but I don't know what that means. We don't use as many trains here in the U.S. as those crazy Europeans :)

Title: Re: Trains and distances
Post by Icarus on Dec 30^th, 2004, 7:53am

He means they are following the same route - but they could be on parallel sets of rails on that route. The U.S. is so big that it is uneconomical for us to do this much. Most traces in the U.S. consist of a single set of rails. Other than the occasional sidings - put in so that trains could pass each other, parallel rails on the same route are only found in congested areas.

Title: Re: Trains and distances
Post by Grimbal on Jan 1^st, 2005, 2:18pm

What I meant is that if the route makes a big S, the train coming from A might be closer to B than the one coming from B at the time of the collision.

Of course, even at high speed, the trains will not collide into a single point, so they must not be at the same distance.