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### #21

Posted 16 September 2011 - 08:50 AM

....................................................Arrival.............................................Departure..............................

Left side........................................6:00...................................................6:01..................................

Right side......................................6:01...................................................6:02..................................

6:03.................No train............

6:04.................No train............

6:05.................No train............

6:06.................No train............

Left side.......................................6:07....................................................6:08..................................

right side......................................6:08....................................................6:09..................................

and so on................

### #22

Posted 16 September 2011 - 11:25 AM

### #23

Posted 16 September 2011 - 02:19 PM

I was sitting in a subway station No. 12(toatal stations are 24).

On this line are several trains transporting passengers from staion(No. 1 ) till the end station( No. 24),then each train will continue the journey from side to side(both sides are connected together at each end).I noticed that after each 4 Minutes a train arrives this station from left side toward the right side,one minute later another train arrives the station but to the opposit direction,and so on.

If each train stays in each station exactly one minute( notice that the train at each end will make a curve and return back to that staion,just like a circle).

Howmany trains are there on this line?

Hence, I agree with bhramarraj that this would mean, in your example above, that the next train from the left would arrive at 6:04. Did we loose something in translation?I`ll give another example, in more details:

....................................................Arrival.............................................Departure..............................

Left side........................................6:00...................................................6:01..................................

Right side......................................6:01...................................................6:02..................................

6:03.................No train............

6:04.................No train............

6:05.................No train............

6:06.................No train............

Left side.......................................6:07....................................................6:08..................................

right side......................................6:08....................................................6:09..................................

and so on................

### #24

Posted 16 September 2011 - 04:46 PM

So the question that needs to be clarified: How often do trains arrive FROM THE LEFT?

### #25

Posted 17 September 2011 - 12:14 AM

I`ll give another example, in more details:

....................................................Arrival.............................................Departure..............................

Left side........................................6:00...................................................6:01..................................

Right side......................................6:01...................................................6:02..................................

6:03.................No train............

6:04.................No train............

6:05.................No train............

6:06.................No train............

Left side.......................................6:07....................................................6:08..................................

right side......................................6:08....................................................6:09..................................

and so on................

To be curt...

is it

Train to station = 4 minutes

Stationed train = 1minute

Opposite train arrival = the time of the departing train

Train curving from station 24 to the original station (No.1 infer) = 5 minutes?

**Edited by Phaze228, 17 September 2011 - 12:14 AM.**

### #26

Posted 17 September 2011 - 01:05 AM

### #27

Posted 17 September 2011 - 04:07 PM

Sorry about the mistake...this example is the right one...i.e. 2 trains(left then right,in one minute interval),then 4 minutes(No trains),and so on.Hence, I agree with bhramarraj that this would mean, in your example above, that the next train from the left would arrive at 6:04. Did we loose something in translation?

### #28

Posted 17 September 2011 - 06:37 PM

23x+24=6n and

25x+24=6m

This gives 23m=25n-8

Which has a solution of m=n=4 but this again gives x=0 so if we want the first set of integers that give us a nonzero transit time we find:

m=29,n=27. This gives x=6 minutes. So the track has

*trains, each 6 minutes apart. For explanation of what I did here see my first post.*

**56**### #29

Posted 18 September 2011 - 12:54 AM

### #30

Posted 18 September 2011 - 04:12 PM

If they are 25 trains,,,and there are only 24 stations,,,that means there should be only one minute interval between train and the next one,and with the extra train (No.25) would be no interval between it and the next train.I (and, I think others) have made a false assumption:

Spoiler for False assumption madeSpoiler for Solution

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