>>>Hi everybody,
>>>
>>>This is a puzzle, which could be asked on a interview. I could not find a best answer.
>>>
>>>There is a 100 floor building. You have two glass balls. You need to find out the floor number, starting from which these balls will broke by minimal number of steps.
>>>
>>
>>What is definition of a step in this case?
>
>I think, one dropping of a ball is a step.

Are you saying that I need to find out the lowest floor of this building where a glass ball will break when dropped and I need to explain how it could be determined in the least number of actions?

Renoir