A barrel contains 10l of whiskey, another one contains 10l of coca-cola. If I do the following operation in two steps:
1 step) with a glass I transfer 200ml of whiskey from the first barrel to the second one, and I mix the barrel very well.
2 step) After that, with a glass I transfer 200ml of the whiskey/coca-cola mix from the second barrel to the first one, and I mix very well. This way, now the two barrels contain again exactly 10l of liquid each.
If I repeat these two steps ten times, at the end will I have more coca-cola in the whiskey barrel or more whiskey in the coca-cola barrel?