SOLUTION: Hi A man can row 8km per hour in still water. If it takes him 3 times as long to row upstream as to row down the river what would be the rate of current in the stream. Thanks

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Question 1168214: Hi
A man can row 8km per hour in still water. If it takes him 3 times as long to row upstream as to row down the river what would be the rate of current in the stream.
Thanks
Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.

The "time" equation is 


    d%2F%288-x%29 = 3%2A%28d%2F%288%2Bx%29%29,


where x is the unknown rate of the current;  d is the on way distance.


We can cancel the factor d in both sides.  Then we have


    1%2F%288-x%29 = 3%2F%288%2Bx%29.


To solve this equation, first cross-multiply; then simplify


    8 + x = 3*(8-x)

    8 + x = 24 - 3x

    x + 3x = 24 - 8

    4x     = 16

     x     = 16/4 = 4.


ANSWER.  The rate of the current is 4 km/h.

Solved.