Kim rowed 45mph Upstream.
The next day she rowed the same distance Downstream taking her 4hrs less.
If she can row 7mph in still water,
find the speed of the current river.
**Note: this question does not state how much time she's been rowing for.
That's why I don't understand how to solve this question..
since time = distance/speed, if the current's speed is x mi/hr, you have
45/(7+x) = = 45/(7-x) - 4
Now just find x.