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

    Question

    Two cars start from a place with a speed of 45 km/hr at

    an interval of 10 minutes. What is the speed of a man coming from the opposite direction towards the place if he meets the cars at an interval of 9 minutes?
    A 12 km/hr Correct Answer Incorrect Answer
    B 20 km/hr Correct Answer Incorrect Answer
    C 15 km/hr Correct Answer Incorrect Answer
    D 5 km/hr Correct Answer Incorrect Answer
    E 10 km/hr Correct Answer Incorrect Answer

    Solution

    Distance covered in 10 minutes at 45 km/hr =45 x (10/60) Distance covered in 9 minutes at (45 + x) km/hr = (9/60) x (45 + x) Now, Distance covered in 10 minutes at 45 km/hr = Distance covered in 9 minutes at (45 + x) km/hr ⇒ 45 x (10/60) = (9/60) x (45 + x) ⇒ 45 x 10 = 405 + 9x ⇒ 450 = 405 + 9x ⇒ 9x = 450 - 405 = 45 ⇒ x = 5 km/hr

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