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

    Question

    A boat covers 13 km upstream in 52 min. If the speed of

    the current is 3 km / h, then in how much time will it cover 40 km downstream?
    A 2 Correct Answer Incorrect Answer
    B 4 Correct Answer Incorrect Answer
    C 1 Correct Answer Incorrect Answer
    D 3 Correct Answer Incorrect Answer

    Solution

    Let the speed of boat in still water =B and speed of stream =S Speed of boat in upstream =B-S=13×60/52 =15km/h S=3km/h B=18km/h Speed of boat in downstream =B+S=21km/h Take time cover 40km in downstream =40/21 =1(19/21)

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