Question 894989
The current on a portion of the Mississippi River is 3 miles per hour. A barge can go 6 miles upstream in the same amount of time it takes to go 10 miles downstream. Find the speed of the boat in still water. 
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let x=speed of boat in still water
(x+3)=speed of boat downstream
(x-3)=speed of boat upstream
Travel time=distance/speed
..

6/(x-3)=10/(x+3)
10x-30=6x+18
4x=48
x=12
speed of the boat in still water=12 mph