Determine the largest 3 - digit prime factor of 2000 C 1000.
n C r denotes the number of combinations of n things taking r at a time.
I did the same thing initially. If you choose 1000 of 2000 items, and the order that you choose the items matters then the equation is:
n! / r!.
However, if the order does not matter, (1,2 is the same as 2,1) then the equation becomes:
n! / (r! * (n-r)!)
Posted by Leming
on 2006-05-12 12:44:16