Seven sportsmen (named A,B,C,D,E,F and G) buy 7 hats choosing randomly out of 4 available colors (say G,R,W and Y).
What is the probability that all the colors were chosen?

(In reply to Solution by John zadeh)

The problem with your solution is that missing one color and missing some other color are not mutually exclusive events, so their probabilities cannot be added (or multiplied by four for four equally probable events).  There is overlap, as for example a situation in which both Y and W were missing has been counted twice.

BTW, why so many copies of the same post?

Posted by Charlie on 2010-04-28 11:12:54