Permutation / Computation Guide

il_bandito
Fri, 02 Sep 2005 11:53:17 +0000

Subtract the number of possible permutations containing 2 on either end from the total number of permutations.

So:

2 x x x x, There are 4 items, so unique permutations with 2 on the left side end is 4!, which is 24. There is an equivalent number of unique permutations for the 2 being on the right side. Therefore, total permutations with 2 on either side is 4! x 2 which is 48.

Total permutations is 5!, so 5! - 48 = 72.