How Much Time Will The Train Take to Travel 108 km?

A train takes 20 second to cross a person a person who is travelling at a speed of 9 km/hr in the same direction. If the length of the train is 150  meter, then how much time will the train take to travel 108 km?

  1. 4 hours
  2.  10.8 hours
  3.  3 hours
  4.  5 hours
Manish Listener Asked on 25th July 2015 in Maths.
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  • 1 Answer(s)

    Answer: (3) 3 hours
    Explanation:-
    Let the speed of a train = X km/h
    Speed of a person = 9 km/h
    Speed in m/sec = 9 x 5/18
    = 5/2 m/sec
    The length of the train = 150 m
    According to the question,
    150 /(X – 5/2) = 20
    150 x 2/(2 X – 5)  = 20
    300 = 20 (2 X – 5)
    300 = 40 X – 100
    40 X = 300 + 100
    40 X = 400
    X = 400/40
    X = 10 m/sec
    Speed in km/h = 10 x 18/5
    = 18 x 2 = 36 km/h
    The speed of the train = 36 km/h

    Time taken by train to covered the distance 108 km = 108/36
    = 3 h.
    Hence,the answer is (3) 3 hours.

    Anurag Mishra Professor Answered on 31st July 2015.
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