Question

    A train 420 metre long takes 72 sec to cross a man

    running at a speed of 4 km/hr in the direction opposite to that of train. What is the speed of the train?
    A 23 km/hr Correct Answer Incorrect Answer
    B 18 km/hr Correct Answer Incorrect Answer
    C 30 km/hr Correct Answer Incorrect Answer
    D 17 km/hr Correct Answer Incorrect Answer

    Solution

    Let the speed of the train be x Relative speed = (x + 4) km/hr ⇒ (x + 4) = (420 × 18)/(72 × 5) ⇒ (x + 4) = (7560)/(360) ⇒ x + 4 = 21 ⇒ x = 21 – 4 = 17 km/hr

    Practice Next