Question 1108941: Sue rowed her boat across Lake Bend and back in 3 hours. IF her rate returning was 3 mph less than the rate going, and if the distance each was 7 miles, find her rate going.
I already tried doing this problem and the answer(s) that I got was 1.19 going and 1.81 returning. [the answers were rounded).
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! Her rate returning was 3 mph LESS than the rate going,
so her rate going could not have been 1.19 mph.
 = Sue's rowing rate (speed) going (in mph) is what we are asked for.
 = Sue's rowing rate returning (in mph)
Each way was 7 miles, so it took Sue
 hours for the going across, and
 hours for the return trip.
The total time in hours was
We need to solve that equation for .
The solutions to that equation are  ,
which round to approximately  and  .
However,  would make  ,
and we cannot have a negative speed.
So, with a more reasonable number of significant digits,
we could say that Sue's rate going across was  ,
which would make the rate  for the return trip.
That would have made the approximate rowing times
   going across the lake, and
  returning.
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