How do I solve this confusing problem?

Question

Jan rows a canoe down stream (with the current pushing her) at a rate of 6.6 mph. She then turns around and rows against the current and travels at a rate of 3.4 mph. If she takes her canoe to a lake and rows in still water, at what rate would her canoe move?

Answer 1

Let x = rate in still water

     r = rate of current

 

Then, x+r = 6.6

         x-r = 3.4

 

Adding the equations, we get 2x = 10

 

                                             So, x = 5 MPH