Question

    A train can cross a pole in 42 seconds. While if the

    train increased its speed by 55% then time taken by it to cross 231 metres long platform is 42 seconds. Find the time taken by the train to cross a 100 metre long tunnel.
    A 56 seconds Correct Answer Incorrect Answer
    B 58 seconds Correct Answer Incorrect Answer
    C 46 seconds Correct Answer Incorrect Answer
    D 44 seconds Correct Answer Incorrect Answer
    E 52 seconds Correct Answer Incorrect Answer

    Solution

    Let speed of train is ‘x’ m/s So, length of train = 42 × x = 42x metres And, 42x + 231 = 1.55 × x × 42 Or, 23.1x = 231 Or, x = 10 m/s So, length of train = 42 × 10 = 420 metres Desired time = (420 + 100)/10 = 52 seconds

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