Question:
There are 10 black socks and 10 white socks in a drawer. Now you have to go out wearing your shoes.
So how many maximum number of times do you need to remove the sock from the drawer so that you can go out?
You can remove only 1 sock at a time.
You can’t look at the drawer while removing the socks.
Solution: 3
The worst case is when the socks from the first 2 pick do not match. However, in the third pick, since there are only 2 colors, the sock will match one of the socks already with me.
This is also widely known as the "Pigeon Hole Principle".