This has nothing to do with photography, but mainly with the fun of solving mental and geometric puzzles. Some are more difficult, others easier, but all of them have in common that they make us exercise our gray cells and keep our brain in shape. For some, the use of a calculator (which is part of every operating system) is recommended. All puzzles and tasks are the fruit of my gray cells, but I encourage you to freely share them around and come up with some yourself.
Lots of fun and gray cell exercise!
Stick
A metal rod is stuck into the bottom of the lake. Half of the rod sticks under the bottom of the lake, and one third of the rod is standing in the water. There are still 6 meters above the surface of the bar.
How long is the whole rod?