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October Train Puzzle

October Train Puzzle - 5 October

An express train takes 3 seconds to enter tunnel which is 1 km long.
If it is traveling at 120 km an hour, how long will it take to pass completely through the tunnel

For Solution : Click Here


  1. cannot determined since the length of train is not givn

  2. can someone say why?

  3. the train is traveling at 120 km/h, that means it is travelling at 33.333333 m/s..since it takes 3 s to enter the tunnel, it means the train is 99.999999 m long(aprox. 100 m)..once it has entered, it has 900 m left for it to exit..there will have to pass 27 s (900/33.333333) for the train to reach the exit and another 3 s to completely get out, therefore the answer is 30 s.

  4. 120 KM per hour. that is 2 KM per minute. That is 60 seconds 2 KM.30 seconds 1 km and 3 seconds to enter. there fore 33 seconds it will take to cross the tunnel.

  5. The length of the train = (120x3x1000)/3600 = 100 m
    The time to pass through = (1.1x3600)/120 = 33 s