a man can row 7.5km/hr in still water and he takes 6.5 times as long as to row upstreams as to downstream. the speed of the current is?
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The speed of the stream either increases (downstream) or decreases the speed of man.
So if speed of current is x.
His speed upstream will be 7.5+x.
And downstream will be 7.5-x.
Now according to question he takes 6.5 times as long to stream upwards meaning his speed going up is 6.5 times his speed going down.
So 7.5+x=6.5(7.5-x)
7.5+x=48.75-6.5x
x+6.5x=48.75-7.5
7.5x=42.25
x=42.25/7.5
x=5.63333
So if speed of current is x.
His speed upstream will be 7.5+x.
And downstream will be 7.5-x.
Now according to question he takes 6.5 times as long to stream upwards meaning his speed going up is 6.5 times his speed going down.
So 7.5+x=6.5(7.5-x)
7.5+x=48.75-6.5x
x+6.5x=48.75-7.5
7.5x=42.25
x=42.25/7.5
x=5.63333
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