Question

    Speed of a boat in still water is 10 kmph and speed of

    stream is 7 kmph. A man rows to a place at a distance of 51 km and come back to starting point. The total time taken by him is:
    A 33 hrs Correct Answer Incorrect Answer
    B 24 hrs Correct Answer Incorrect Answer
    C 22 hrs Correct Answer Incorrect Answer
    D 20 hrs Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Rate upstream = 10 – 7 = 3 kmph Rate downstream = 10 + 7 = 17 kmph Time taken to go upstream = 51/3 = 17 hr Time taken to go downstream = 51/17 = 3 hr Total time = 17 + 3 = 20 hrs

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