Question

    Speed of a boat in still water is 15 kmph and speed of

    stream is 12 kmph. A man rows to a place at a distance of 54 km and come back to starting point. The total time taken by him is:
    A 13 hrs Correct Answer Incorrect Answer
    B 11 hrs Correct Answer Incorrect Answer
    C 16 hrs Correct Answer Incorrect Answer
    D 20hrs Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, For upstream(against the stream), the effective speed is (V-S), where V is the speed of boat = 15km/h S is the speed of the styream = 12km/h downstream speed (v+s)=15+12=27km/h Upstream speed(V-S) = 15 - 12 = 3km/h Now, Total time = [Distance/speed]  Time = (54/27) +(54/3)  time = 2+18 =20hours 

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