New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    Train A running at 81 km/h takes 72 sec to overtake

    train B, when both the trains are running in the same direction, but it takes 36 sec to cross each other if the trains are running in the opposite direction. If the length of train B is 600 meters, then find the length of train A (in meters)
    A 520m Correct Answer Incorrect Answer
    B 440m Correct Answer Incorrect Answer
    C 560m Correct Answer Incorrect Answer
    D 480m Correct Answer Incorrect Answer

    Solution

    Given- speed of A = 81km/h, distance of B = 600m Let speed of B = B, and distance of A = x  When both the trains are running in the same direction  (A – B) × 72 = x + 600 5/18 (81 – B) × 72 = x + 600 ... (1) When both the trains are running in the opposite direction  5/18 (81 + B) × 36 = x + 600 ... (2) From (1) and (2) 5/18 × (81 – B)72 = (81 + B) 36 ×5/18  81 × 2 – 2B = 81 + B 3B = 81  B = 27  Put the value of B in (1)  (81 – 27) × 72 × 5/18 = x + 600  1080 – 600 = x  x= 480 m

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