Q: another perms. (1 Viewer)

marsesbars

Member
Joined
Oct 31, 2002
Messages
41
Total of 10 letters.

1) First, let's place the two N's. We can't have them at either end, so they must be in the middle 8 positions. Now the N's are indistinct from each other, so it's 8C2 ways to place them.

2) Place the rest of letters (ignore the N's for a moment). There are 8 left and 8 positions to be filled. All letters are distinct except for
* 2 T's
* 2 I's
so,
Code:
  8!
-------
2! 2!
3) Combine them. You multiply them, so you get
Code:
  8!
-------  x 8C2
2! 2!
 

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