In the dark, you are drawing socks from a drawer, one at a time (your family is asleep and you don't want to wake them...). The drawer contains 12 red socks, 11 white socks, 10 black socks, and 9 blue socks. What is the minimum number of socks you must draw from the drawer to be absolutely sure you have all of at least one of the colors?0
That was my first answer, pixie- but I'd misinterpreted the question in the same way as I think you have. We don't want one of each- we want a full set of one colour
I know from experience it's not a good idea to pose these sort of theoretical (artificial )problems in a secondary school probability lesson, but I enjoy doing them, especially after a beer or two
That wasn't the question. The question was "12 red socks, 11 white socks, 10 black socks, and 9 blue socks. What is the minimum number of socks you must draw from the drawer to be absolutely sure you have all of at least one of the colors?"
Either you get one first time. Or you draw all the white ones first, then get a colour.