There are fish numbered through at one end of an aquarium. They all start swimming at the same time to the other end of the aquarium. Once a fish reaches an end of the aquarium, it turns around immediately and continues swimming in the other direction.
Fish swims with speed , fish swims with speed , fish swims with speed , and so on.
Will the fish all be at the same end of the aquarium at the same time again?
An example aquarium with fish.