In my bedroom there are 20 black, 20 white, 30 red and 15 blue socks available. I went inside my room and it is all dark and no electricity available.
Now, I need to have two pairs of Socks for my road trip. All socks of same colour are exactly same. You have to tell me that in all how many socks minimum should I take outside my room that I will surely have two pairs of Socks. These two pairs can be of the same colour or the different colour. But in the same pair, socks have to be of same colour.
So what is the minimum number of socks required for me to have at least two pairs of socks?