dumb business class math problem

[ric1287]

Been out of the math game for a couple years ......

how many permutations of the letters ABBCCCDDDDEIOU are there?

can't do the simple P(n, r) because of the repeating letters. Any help?

 

[RapidSnail]

87,178,291,200?



Edit: Or do you want combinations: 1?

You really haven't made clear the size of the set you want, so I assumed 14.



Edit 2: I guess my permutation answer doesn't work since I just realized that you don't want repeating characters. In that case, the repeating characters would serve as nothing more than filler making n, and r as well, equal to 8.

Final Answer: 40,320

 

[CPA]

42

 

[cliftonite]

14!/(14-8)! ?

 

[calvinbiss]

14!

 

[RapidSnail]

Originally posted by: cliftonite
14!/(14-8)! ?

That wouldn't work because you're still deriving your answer from the original 14 characters which include repetitions. Limiting the output to 8 characters still allows for the inclusion of repetitions.

 

[3NF]

ABBCCCDDDDEIOU

I think it is 14!/(1!*2!*3!*4!*1!*1!*1!*1!)

 

[DrPizza]

Permutations of Mississippi:

11!
--------
4! * 4 * 2!

divide because there are 4 s's, 4 i's, and 2 p's.

 

[ric1287]

think i got it.....

14! with no repeats, so divide out the repeats......14!/(4! 3! 2!)

 

[ric1287]

Originally posted by: DrPizza
Permutations of Mississippi:

11!
--------
4! * 4 * 2!

divide because there are 4 s's, 4 i's, and 2 p's.

haha nice, i saw the ------- and thought the rest was your signature. thanks.

 

[esun]

Useful to know: http://en.wikipedia.org/wiki/Multinomial_theorem

 

[RapidSnail]

Originally posted by: esun
Useful to know: http://en.wikipedia.org/wiki/Multinomial_theorem

Eh, didn't know about that.

 

[3NF]

Is this your class?

http://www.math.uic.edu/~rmlow...0/160specialhw2su7.pdf

Math160 - isn't that Kindergarten math?

 

[her209]

Combinatorics... w00t!

 

[DrPizza]

Originally posted by: ric1287

Originally posted by: DrPizza
Permutations of Mississippi:

11!
--------
4! * 4 * 2!

divide because there are 4 s's, 4 i's, and 2 p's.

haha nice, i saw the ------- and thought the rest was your signature. thanks.

I had a typo though - there's supposed to be a factorial after the 2nd 4 as well... Now I know why I had to take out that "@" sign - I hit the wrong key