Question

    300 metre long train ‘A’ is running with a speed of

    25.2 km/hr. Train ‘B’ which is 364 metre long is running with a speed of 90 km/h in opposite direction of train ‘A’. For how much time, the smaller train is completely obscured by the larger train when they cross each other?
    A 2 second Correct Answer Incorrect Answer
    B 1 second Correct Answer Incorrect Answer
    C 3 second Correct Answer Incorrect Answer
    D 7 second Correct Answer Incorrect Answer
    E 5 second Correct Answer Incorrect Answer

    Solution

    Length of smaller train = 300 metre Speed of smaller train = 25.2 × (5/18) = 7 m/s Length of bigger train = 364 metres Speed of bigger train = 90 × (5/18) = 25 m/s Since, the smaller train is completely obscured by larger train, therefore, extra length of larger train = 364 – 300 = 64 metres Relative speed of trains ‘A’ and ‘B ‘= 7 + 25 = 32 m/s (Since, the trains are running in opposite direction) Required time = 64/32 = 2 second

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