Final answer:
To be sure that he has at least two blue socks, the person must continue taking socks out until he has either picked two blue socks or until he has picked all the socks out of the drawer.
The person would need to take out a minimum of 13 socks to be sure he has at least two blue socks.
Step-by-step explanation:
To be sure that he has at least two blue socks, the person must continue taking socks out until he has either picked two blue socks or until he has picked all the socks out of the drawer.
The worst-case scenario is if the person picks out all the red socks first before picking any blue socks. In this case, he will have to take out all 12 red socks before picking the first blue sock, and then one more sock to guarantee at least two blue socks. So, the person would need to take out a minimum of 13 socks to be sure he has at least two blue socks.