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#1 2006-12-01 05:44:46

Dharshi
Member
Registered: 2006-10-31
Posts: 56

Equation ?????

How many words, with or without meanings, can be formed using all the letters of the word       EQUATION, using each letter exactly once?


I need help with this problem.


Can any onneeeeeeeeeeee help me??????;)

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#2 2006-12-01 06:14:21

pi man
Member
Registered: 2006-07-06
Posts: 251

Re: Equation ?????

How many different letters can be the first letter of the "word"?   There are 8 letters in EQUATION and no letter appears twice, so 8 different letters can be the first letter of the word.   

How many letters can be the 2nd letter of the word?   All of them but the one that's being used as the first letter.   So that's 7.    We now have 56 combinations for the first 2 letters of the word.   

Keep using this method and it will become apparent that the answer will be 8*7*6*5*4*3*2*1.   That's 8 factorial, usually written as 8!.   That's equal to 40320.

It's important to note that no letter appeared twice in EQUATION.   If you were rearranging letters that had repeats, you have to take some additional steps.   If one letter is repeated twice, you divide your answer by 2!.   If one letter is repeated 3 times, divide by 3!.  If 2 letters are repeated twice, divide by (2! *2!).

AABCDEFG = 8! / 2! different arrangements
AAABCDEF = 8! / 3! different arrangements
AABBCCDD = 8! / (2! * 2! * 2! * 2!)

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#3 2006-12-01 06:16:33

Devantè
Real Member
Registered: 2006-07-14
Posts: 6,400

Re: Equation ?????

I think this may be a trick question.

Dharshi said with or without meanings.

EQUATION has 8 letters.

8! = 40320

But then you said they have to be words. I don't recall any words that start with QN.

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#4 2006-12-05 02:48:37

Dharshi
Member
Registered: 2006-10-31
Posts: 56

Re: Equation ?????

y =x +1

How can you state the reason that this is a function?:(

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#5 2006-12-09 04:41:02

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

Re: Equation ?????

This is an equation.
Function is for example:


IPBLE:  Increasing Performance By Lowering Expectations.

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