ok, so if it breaks on the 1st floor what does that mean that the 0th floor ?!? is the " highest floor an egg can be dropped from without breaking".
The statement says :
"A building has N floors. One of the floors is the highest floor an egg can be dropped from without breaking."
If the egg can break on the 1st floor, then the building has N floors (1st to Nth) + the 0th floor, so it has in fact N + 1 floors not N.
You say "Based on the results ...", but that's exactly the point : the results are false because they contradict the statement.