A boat is heading upstream when a float is dropped overboard and carried downstream. After 1 hour, when the boat is has traveled 2.0 km farther upstream, it turns around and catches up with the float 5.0 km downstream from the turnaround point. If the boat travels with constant velocity: How fast does the river flow? What is the boats speed in still water? I really have no idea where to start with this really. I'm having trouble understanding how to find the velocities and such without a time variable. Any help that you guys can give will be much appreciated.