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Did You Solve It? Get the Answer to the Riddle of E-News Issue No. 02, March 2014

What is the mix ratio?

Brain teaser: Drinking glasses

In front of you is a beer glass filled with 250 ml of beer. There is also a tumbler filled with 250 ml of lemonade.

You remove a tablespoon of liquid from the beer glass and pour it in the tumbler. Then you remove the same amount of liquid from the tumbler and pour it back in the beer glass. There is the same amount of liquid in both glasses again.

Is there now more beer in the tumbler than lemonade in the beer glass?

Answer

No, because the mix ratio in both glasses has remained the same.

Because there is the same amount of liquid at the end of the experiment, as much lemonade must have been taken out of the tumbler as there is beer remaining in the tumbler. It makes no difference whether it was stirred or not.

Try it with the following example: assume that the liquid in the second tablespoon contains 90% lemonade. You add this to the beer. There is 90% (one tablespoon) of beer missing from the beer glass. This amount has remained in the lemonade. It can be concluded that only an exchange of liquid has taken place, because there is the same amount of liquid in both glasses again.