You have a cube of ice floating in a glass of water. The question is what fraction of the ice will be above the water line? Assume that the ice is not bobbing.

Most of you have probably heard the answer to this before. But please provide a proof or solution, along with your assumptions.

Somebody has already commented in regard of the formula to be applicable to your question.  I could not deny that he is wrong since it is at the normal circumstance with the assumption of pure water.

Do you know that you will definitely float in the dead sea due to the high density of water there.  There is much salt in the sea that cause you to float in the sea.  Similarly, if you place an ice cube there, much fraction of the ice cube will expose in the sea. 

The question does not mention what kind of water.  It can be sea water, river water, drain water or dirty water or whatsoever.  Unless one says that sea water is not water and that is why we cannot assume that it is sea water.  Could one say that the water that is mentioned in the water is not the sea water from the Dead Sea since sea water is not water.

As there is an uncertainty of what kind of water to be used but simply the word, water, in the question, it is up to us to assume whether it is or it is not pure water.  As it is not definitely pure water, the solution is uncertainty and it depends upon the kind of water you use to test.

I apologise if what words are too strong to hurt anybody. 

I have to explain to clarify my point of view.

Thanks