Dropping Eggs


I got this problem from Rustan Leino, who got it from Sophia Drossopoulou and Alex Summers.

I solved it and wrote up my solution.


There's a certain kind of egg about which you wonder: What's the highest floor of a 36-story building from which you can drop an egg without it breaking? All eggs of this kind are identical, so you can conduct experiments. Unfortunately, you only have 2 eggs. Fortunately, if an egg survives a drop without breaking, it's as good as new—that is, you can then conduct another dropping experiment with it. What's the smallest number of drops that's sure to determine the answer to your wondering?

Solution     Reveal