A man can row 9 and 1/3 kmph in still water and finds that it takes him thrice as much time to row up than as to row, down the same distance in the river. The speed of the current is :

3 and 1/3 kmph

3 and 1/9 kmph

4 and 2/3 kmph

none of the above

Let speed upstream is x kmph. Then, speed downstream = 3x kmph. Speed in still water = (1/2)(3x + x) kmph = 2x kmph. => 2x = 28/3 x => = 14/3 Speed upstream = 14/3 km/hr Speed downstream 14 km/hr. Speed of the current = (1/2)[14 - (14/3)] = 14/3 = 4 and 2/3 kmph

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