Two Eggs, 100 Floors

The problem
100 floorsegg 1egg 2find the threshold k

You have two identical eggs and a 100-story building. There exists some floor kk such that:

  • An egg dropped from floor kk or below survives.
  • An egg dropped from any floor above kk breaks.

You want to find kk. Eggs that survive a drop can be reused; broken eggs are gone forever. What's the minimum number of drops you need in the worst case to guarantee finding kk?