If you swim with the current in a river, your speed is increased by the speed of the water; if you swim against the current, your speed is decreased by the water’s speed. The current in a river flows at 0.52 m/s. In still water you can swim at 1.78 m/s. If you swim downstream a certain distance, then back again upstream, how much longer, in percent, does it take compared to the same trip in still water?