Say you go kayaking over a 2 mile stretch of river. The river is flowing at a speed of 1mph. You go 2 miles upstream, and then 2 miles downstream, back to your starting point, for one round trip. Create a function (ie. turn the set-up for the problem above into a variable expression by replacing the following) that relates your speed in still water (x) to the time one round trip takes (f(x)), based on the problem above.