Question from Perms and Combs unit

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SUMMARY

The discussion centers on calculating the number of 5-letter "words" formed from the letters of the word "ELEMENTS" with alternating vowels and consonants. The participant initially calculated 480 combinations by considering two cases: starting with a vowel (v c v c v) and starting with a consonant (c v c v c). However, the correct total is 80, as the participant overlooked the need to divide by 3! to account for the repetition of the letter 'E'. This crucial adjustment corrects the overcounting of arrangements involving identical letters.

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  • Knowledge of vowel and consonant classification in English
  • Ability to apply the factorial function in calculations
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Homework Statement


Given the letters of the word ELEMENTS, how many 5 letter "words" can be found in which vowels and consonants alternate


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The Attempt at a Solution


I see the need to use Cases here because the pattern can either go:

v c v c v

or

c v c v c

So I did:

Case 1 : vowel starts 3 5 2 4 1 = 120
Case 2: consonant starts 5 3 4 2 3 = 360

Add them up to get 480, however the answer says 80. What went wrong? Or was that a typo mistake?
 
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Is there any difference between the first and last E?
 
Don't think so.
 
So how many different ways are there to arrange the vowels?
 
Nevermind, I found out what I did wrong, I forgot to divide each case by 3! for the repetitive E's.
 
What do you mean "nevermind", that was what Nate was pointing out all along.
 

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