13.
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 . [Central Excise ]
3
and 1/3 km/hr 4 and 2/3 km/hr
3
and 1/9 km/hr 14 km/hr
Answer: 4 and 2/3 km/hr
Explanation: 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
