A man has 42 blue socks, 15 red socks, 24 black socks in one box. It is totally dark and can not recognize the colors. How many socks does he have to take out of the box into the light in orders to be sure to have at least two black socks?
A man has 42 blue socks, 15 red socks, 24 black socks in one box. It is totally dark and can not recognize the colors. How many socks does he have to take out of the box into the light in orders to be sure to have at least two black socks?
Explanation
To guarantee at least 2 black socks, consider the worst-case scenario where he draws all non-black socks first.
Total non-black socks = 42 (blue) + 15 (red) = 57
To guarantee 2 black socks, he needs to draw enough socks so that even if the first 57 are non-black, the next draws will include at least 2 black socks.
So, he draws 57 (non-black) + 2 (black) = 59 socks.