If you had an egg to test by dropping it from each floor of a 100 storey building, you'd need to start by dropping it from the first floor, and if it didn't break, go up to the second floor, and if it didn't break, go up to the third floor...
In the worst case scenario, you might have to do 100 tests to find out where it breaks!
It would speed the process up if you had two eggs...
How would you use the extra egg so that you don't need to do so many trials?
Perhaps you might drop the first egg from the 5th floor. If it breaks, use the second egg to test floors 1 to 4.
If it doesn't break, drop the first egg from...
Can you come up with a strategy, using two eggs, to minimise the maximum number of trials you might have to do?
What if there were more floors?
What if you had more eggs?
You may want to use a spreadsheet or write a simple program to tackle parts of this problem.