I've been working on this one and I just can't figure it out. I appreciate all the help:
Two miles upstream from his starting point, a canoeist passed a log floating in the river's current. After paddling upstream for one more hour, he paddled back and reached his starting point just as the log arrived. Find the speed of the current.
I think it may be one of those two-equation problems you need to set up in order to get the answer but I don't know where to start. Thanks for helping me.