Permutation of subsets with like objects Question

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SUMMARY

The discussion focuses on calculating the number of permutations for a subset of 3 objects from a superset of 8 objects, where 5 objects are identical. The initial solution proposed an incorrect calculation involving C(5,2), which was clarified to be 1 due to the identical nature of the objects. The correct answer to the permutation problem is confirmed to be 106, not 196, as initially suggested. This conclusion emphasizes the importance of accurately accounting for identical objects in permutation calculations.

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  • Familiarity with the concept of identical objects in combinatorial problems
  • Basic knowledge of factorial notation
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  • Study the principles of permutations with identical objects
  • Learn about combinatorial formulas, specifically C(n, k)
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Permutations of subsets with like objects Question

Hello, I'd like to know if I solved the question correctly; if not, I'd appreciate some help.

Question:
Calculate the number of permutations for a subset of 3 objects from a superset of 8 objects where 5 are alike.

My solution attempt: (Please see attachment).
 

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Your solution is fine except for the factors like C(5,2). This looks like you are counting the ways of picking 2 objects from 5 identical objects. That's not C(5,2). It's 1.
 
Thank you, you're input helped! I believe the answer is 106, not 196. I was going to post a detailed and neat explanation of how I got 196 but I'm so busy that I can't (which is why it took so long for me to reply); however, since I asked for help and you were nice enough try, the least I can do is post my rough work for you and others to see. I'm pretty sure I got it right this time; if not, someone, let me know.
:smile:
 

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