Three eggs, nine drops: tallest building
Question
You hold identical eggs in a building with floors. There is an unknown critical floor with : an egg dropped from below floor survives undamaged, and an egg dropped from floor or higher breaks. It is known that eggs break from the top floor . What is the largest for which you can always determine using no more than drops?
Short answer
130. With eggs and drops you can distinguish possibilities: the first drop splits the problem into below and above. For this is , so can be found among up to floors. Practically, first drop from floor (since two eggs and drops cover floors), then step up by
Adapted from QuantQuestions.io; question and answer rewritten by SelfMadeQuant.com.
See the hint and the full worked solution in the question bank (free account).
Open the worked solution