How fast does the water in the canal flow?
A swimmer jumps from a bridge over a canal and swims 1 kilometer stream up. After that first kilometer, he passes a floating cork. He continues swimming for half an hour and then turns around and swims back to the bridge. The swimmer and the cork arrive at the bridge at the same time. The swimmer has been swimming with constant effort.
The Question: How fast does the water in the canal flow?
1 km/h
1 km/h
1 km/h
1 km/h
