SOLUTION: Ed can row 5 km downstream in half the time it takes him to row 5 km upstream. If the current is 2 km/hour, how fast can Ed row in still water.

Question 1159231: Ed can row 5 km downstream in half the time it takes him to row 5 km upstream. If the current is 2 km/hour, how fast can Ed row in still water.
Answer by ikleyn(52786) (Show Source): You can put this solution on YOUR website!
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Let r be his rate in still water.


Then the rate downstream is (r+2) km/h; while the rate upstream is (r-2) km/h.


The time to travel 5 km downstream is  ;  The time to travel 5 kn upstream is  .


Now your equation becomes


     = .


To solve it, cross multiply


    5*(r+2) = 2*5*(r-2).


Simplify and solve

    5r + 10 = 10r - 20

    10 + 20 = 10r - 5r

    30      = 5r

     r      = 30/5 = 6.


ANSWER.  Ed's rate in still water is 6 km/h.

Solved.

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