We roll five standard dice (sides numbered 1 to 6) and write down the sum of the top three i.e. of the 3 highest values.
What is the probability to get 15 ?

(In reply to analytical attempt at it by Vishal Gupta)

From your solution:

6,6,3,1,1 and 6,6,3,2,2 have 5!/2!2! = 30 ways each

6,6,3,3,1 and 6,6,3,3,2 have 5!/2!2! = 30 ways each

You forgot to count these twice.  You had 60 + 30 + 30 + 10 = 130.  It should be 60 + 30*2 + 30*2 + 10 = 190.  Otherwise, nicely done.

Posted by hoodat on 2010-11-16 16:21:44