freaking_out
Saddam's new life
find how many arrangements of the letters of the word TRANSITION are possible if the letter N is not at EITHER end.
thanx in advance
thanx in advance
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Q: another perms. (1 Viewer)
- Thread starter freaking_out
- Start date
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,
3) Combine them. You multiply them, so you get
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!
Code:
8!
------- x 8C2
2! 2!