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

    Question

    A boat's speed in still water is 50% greater than the

    speed of a stream, which flows at 12 km/h. Calculate the total time it takes for the boat to cover an 18 km upstream journey and a 45 km downstream journey.
    A 3 hours Correct Answer Incorrect Answer
    B 4 hours Correct Answer Incorrect Answer
    C 5 hours Correct Answer Incorrect Answer
    D 4.5 hours Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Speed of boat in still water = 1.5 X 12 = 18 km/h Upstream speed = 18 - 12 = 6 km/h Downstream speed = 18 + 12 = 30 km/hr Desired time = 18/6 + 45/30 = 3 + 1.5 = 4.5 hours Hence, option d.

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