Question

    The speed of a boat in still water is 8 km/hr and the

    speed of the stream is 1.5 km/hr. A man rows to a place at a distance of 30.875 km and comes back to the starting point. The total time taken by him is:
    A 8 hours Correct Answer Incorrect Answer
    B 13 hours Correct Answer Incorrect Answer
    C 9 hours Correct Answer Incorrect Answer
    D 10 hours Correct Answer Incorrect Answer
    E 14 hours Correct Answer Incorrect Answer

    Solution

    Rate downstream = (8 + 1.5) kmph = 9.5 kmph Rate upstream = (8 – 1.5) kmph = 6.5 kmph According to the question, Time = Distance/Speed Hence, Required time = 30.875/9.5 + 30.875/6.5 = 3.25 + 4.75 = 8 hours

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