SOLUTION: A motorboat goes 5 miles upstream in the same time it requires to go 7 miles downsteam. If the river flows 2 mph, find the speed of the boat still in the water.

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Question 777758: A motorboat goes 5 miles upstream in the same time it requires to go 7 miles downsteam. If the river flows 2 mph, find the speed of the boat still in the water.
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
A motorboat goes 5 miles upstream in the same time it requires to go 7 miles downsteam. If the river flows 2 mph, find the speed of the boat still in the water.
***
let x=speed of boat in still water
x+2=speed of boat downstream
x-2=speed of boat upstream
travel time=distance/speed (same for upstream and downstream travel)
..
5/(x-2)=7/(x+2)
7x-14=5x+10
2x=24
x=12
speed of boat in still water=12 mph