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Combinations! How many.by Elruso
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#1
Jun207, 11:25 AM

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1. The problem statement, all variables and given/known data
How many letter combinations with 9 letters are you able to make with following letters : MATEMATIK? 2. Relevant equations Well its pretty obvious you need to use Combinations. Please explain how you solve this problem, don't write use combinations . I need to know how you think and from which angle you "attack" the problem. 


#2
Jun207, 04:31 PM

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You have 9 letter positions to fill. First lets place the M's. There are two of them, so I have C(9,2) ways. Now lets do the A's. There 2 of them and 7 places left to fill, so I have C(7,2) ways. So far I've got C(9,2)*C(7,2). Can you finish?



#3
Jun307, 03:34 AM

P: 5

So iit´s C(9,2)*C(7,2)*C(5,2)*3*2*1?
In my math book the answer is C(9,2)*C(7,2)*5!..... which i find a little strange. 


#4
Jun307, 04:04 AM

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Combinations! How many.



#5
Jun307, 04:07 AM

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Incidentally, it seemed most clear to me to write the answer as 9! / (2! * 2! * 2!),or, as a multinomial coefficient, [tex]\binom{9}{2 \ 2 \ 2 \ 1 \ 1 \ 1} .[/tex] 


#6
Jun307, 08:47 AM

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