A man can row 4.5 km/hr in still water and he finds that it takes him twice as long to row up as to row down the river. Find the rate of the stream ?

A. 2 km/hr

B. 2.5 km/hr

C. 1.5 km/hr

D. 1.75 km/hr

Answer : C. 1.5 km/hrs

Explanation :

Let the speed of the current be x km/hr.
Upward speed = (4.5 + x) km/hr
Downward speed = (4.5 − x) km/hr.
Let distance travelled be y, then
y / (4.5 − x) = 2y / (4.5 + x)
x = 1.5 km/hr

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Time and Distance

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