You go to your friend's place and decide to stay at night. At night you start feeling cold and he asks you to open the drawer attached with the cupboard and take out socks for all three of you. But he keeps a condition that you have to take out three pairs of same color.
In the drawer, there are 2 red, 4 yellow, 6 purple, 8 brown, 10 white, 12 green, 14 black, 16 blue, 18 grey, and 20 orange socks. The problem is that the room is dark and you can't see anything.
In such a scenario, how many socks will you have to take out to make sure that you have at least three pairs of socks of same color?
Solution:
The worst case will be when you don't take out three pairs of same color will be that you take out 2 red, 4 yellow and 5 of each color. In that manner, you will have to take out 46 socks. But if you take out one more sock, you will have 6 socks of at least one color. Thus in that case, you must take out 47 socks to make sure that you have taken out at least three pairs of same color socks.