Why do combination and permutation have different rules for order?

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Discussion Overview

The discussion revolves around the differences between combinations and permutations, specifically in the context of determining the number of ways to award "Best in Show" and "Honorable Mention" at a dog show with 5 finalists. Participants explore the reasoning behind the application of these concepts in this scenario.

Discussion Character

  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant suggests that the problem is a combination problem, proposing the setup as 5C2.
  • Another participant argues that the problem is a permutation problem because the order of awards matters, leading to a calculation of 5(4) = 20 ways.
  • A later reply confirms the permutation approach, calculating 5P2 and arriving at the same total of 20 ways.
  • Some participants express frustration with the need for detailed explanations, suggesting that textbook resources should be consulted instead.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the problem should be classified as a combination or permutation, with differing opinions on the importance of terminology in this context.

Contextual Notes

There is an unresolved discussion regarding the definitions of combinations and permutations, particularly the assertion that "order does not matter" in permutations, which appears to contradict standard definitions.

nycmathdad
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At a recent dog show, there were 5 finalists. One of the finalists was awarded "Best in Show" and another finalist was awarded "Honorable Mention." In how many different ways could the two awards be given out?

The words "how many ways" reminds of probability. I just don't recall if this is a combination or a permutation.

I will take a guess and say this is a combination problem.

The set up is 5C2.

You say?
 
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nycmathdad said:
At a ...
I will take a guess and say this is a combination problem.

The set up is 5C2.

You say?
I say stop guessing.
You have a textbook.
Look it up laddie.
 
Personally, I would not worry about what it is called! There are 5 dogs anyone of which could be declared "best in show". Once that had been chosen, there are 4 dogs left that could be chosen "honorable mention".

There are a total of 5(4)= 20 ways that could be done.

(Since order, which dog is "best in show" and which is "honorable mention", is relevant, this is a "permutation" problem but, as I say, that is really not important.)
 
Country Boy said:
Personally, I would not worry about what it is called! There are 5 dogs anyone of which could be declared "best in show". Once that had been chosen, there are 4 dogs left that could be chosen "honorable mention".

There are a total of 5(4)= 20 ways that could be done.

(Since order, which dog is "best in show" and which is "honorable mention", is relevant, this is a "permutation" problem but, as I say, that is really not important.)

Are you saying that that 5C2 should be 5P2?

Let me see.

5P2 = 5!/(5 - 2)!

5P2 = 120/(3)!

5P2 = 120/6

5P2 = 20 ways.

When it comes to combination versus permutation, in terms of combination order does matter. Order does not matter in terms of permutation. Can you explain why that is the case using a simple math example for both cases?
 
nycmathdad said:
...
When it comes to combination versus permutation, in terms of combination order does matter. Order does not matter in terms of permutation. Can you explain why that is the case using a simple math example for both cases?
There you go again asking volunteer helpers to post a war and peace explanation for something that you could just read from your textbook. Read your book. Reading is good for you.
 

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