Question

A drawer contains 12 red and 12 blue socks, all unmatched. A person takes socks out at random in the dark. How many socks must he take out to be sure that he has at least two blue socks?

(a) 18

(b) 35

(c) 28

(d) 14

This question was addressed to me in a national level competition.

The query is from Counting in division Counting of Discrete Mathematics

Answer 1

The correct option is (d) 14

For explanation I would say: Given 12 red and 12 blue socks so, in order to take out at least 2 blue socks, first we need to take out 12 shocks (which might end up red in worst case) and then take out 2 socks (which would be definitely blue). Thus we need to take out total 14 socks.