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Train Puzzle

Train Puzzle - 15 August

Charles walks over a railway-bridge. At the moment that he is just ten meters away from the middle of the bridge, he hears a train coming from behind. At that moment, the train, which travels at a speed of 90 km/h, is exactly as far away from the bridge as the bridge measures in length. Without hesitation, Charles rushes straight towards the train to get off the bridge. In this way, he misses the train by just four meters! If Charles would, however, have rushed exactly as fast in the other direction, the train would have hit him eight meters before the end of the bridge.

What is the length of the railway-bridge?

For Solution : Click Here


  1. Length of bridge is 24m.

  2. how to get to soln ??

  3. If the bridge is 2Lm long then by the escape route L-10m are run in the time the train travels 2L-4m. By the other route L+2m are run in the time the train covers 4L-8m. Since the train covers twice the distance in the second case, L+2 must be twice L-10 so L+2=2L-20 and L=22. The bridge is therefor 44m long.

    To escape, Charles had to run 12m in the time the train covered 40m so he had to run @ 27Km/Hr.

    All the above assumes that Charles instatly reached 27Km/Hr which is improbable but without information as to how fast he could accelerate we can do nothing else.

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