Permutation Help! [closed]
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How many possible ways to organize a set of natural numbers 1,2,3 ..., 2n so that each even number is in sequence in the even place
combinatorics permutations
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closed as off-topic by José Carlos Santos, drhab, N. F. Taussig, Namaste, mrtaurho Jan 23 at 11:54
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How many possible ways to organize a set of natural numbers 1,2,3 ..., 2n so that each even number is in sequence in the even place
combinatorics permutations
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closed as off-topic by José Carlos Santos, drhab, N. F. Taussig, Namaste, mrtaurho Jan 23 at 11:54
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, drhab, N. F. Taussig, Namaste, mrtaurho
If this question can be reworded to fit the rules in the help center, please edit the question.
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You can first populate the even numbers. So that's the same as asking, "in how many ways can you order the even numbers between 1 and $2n$". And after that you can consider the odd numbers (put them to their places).
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– Matti P.
Jan 23 at 10:31
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Welcome to Math.SE. Take a look at How to ask a good question at Math.SE. To avoid downvotes and closing you should add your own efforts to the question, and tell us where you got stuck.
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– drhab
Jan 23 at 10:48
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$begingroup$
How many possible ways to organize a set of natural numbers 1,2,3 ..., 2n so that each even number is in sequence in the even place
combinatorics permutations
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How many possible ways to organize a set of natural numbers 1,2,3 ..., 2n so that each even number is in sequence in the even place
combinatorics permutations
combinatorics permutations
asked Jan 23 at 10:27


Viliam GlézlViliam Glézl
31
31
closed as off-topic by José Carlos Santos, drhab, N. F. Taussig, Namaste, mrtaurho Jan 23 at 11:54
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, drhab, N. F. Taussig, Namaste, mrtaurho
If this question can be reworded to fit the rules in the help center, please edit the question.
closed as off-topic by José Carlos Santos, drhab, N. F. Taussig, Namaste, mrtaurho Jan 23 at 11:54
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, drhab, N. F. Taussig, Namaste, mrtaurho
If this question can be reworded to fit the rules in the help center, please edit the question.
$begingroup$
You can first populate the even numbers. So that's the same as asking, "in how many ways can you order the even numbers between 1 and $2n$". And after that you can consider the odd numbers (put them to their places).
$endgroup$
– Matti P.
Jan 23 at 10:31
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Welcome to Math.SE. Take a look at How to ask a good question at Math.SE. To avoid downvotes and closing you should add your own efforts to the question, and tell us where you got stuck.
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– drhab
Jan 23 at 10:48
add a comment |
$begingroup$
You can first populate the even numbers. So that's the same as asking, "in how many ways can you order the even numbers between 1 and $2n$". And after that you can consider the odd numbers (put them to their places).
$endgroup$
– Matti P.
Jan 23 at 10:31
$begingroup$
Welcome to Math.SE. Take a look at How to ask a good question at Math.SE. To avoid downvotes and closing you should add your own efforts to the question, and tell us where you got stuck.
$endgroup$
– drhab
Jan 23 at 10:48
$begingroup$
You can first populate the even numbers. So that's the same as asking, "in how many ways can you order the even numbers between 1 and $2n$". And after that you can consider the odd numbers (put them to their places).
$endgroup$
– Matti P.
Jan 23 at 10:31
$begingroup$
You can first populate the even numbers. So that's the same as asking, "in how many ways can you order the even numbers between 1 and $2n$". And after that you can consider the odd numbers (put them to their places).
$endgroup$
– Matti P.
Jan 23 at 10:31
$begingroup$
Welcome to Math.SE. Take a look at How to ask a good question at Math.SE. To avoid downvotes and closing you should add your own efforts to the question, and tell us where you got stuck.
$endgroup$
– drhab
Jan 23 at 10:48
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Welcome to Math.SE. Take a look at How to ask a good question at Math.SE. To avoid downvotes and closing you should add your own efforts to the question, and tell us where you got stuck.
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– drhab
Jan 23 at 10:48
add a comment |
2 Answers
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since there are 2n numbers so there are n even numbers and n odd numbers
So all the n even numbers can be arranged at even places in n! ways and the odd numbers in n! ways at odd places
So the possible ways to arrange them is ( n! x n! ) ways.
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add a comment |
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If all the even numbers are put on the even places, only the odd places are left for the odd numbers. Then the set of possibilities is the cartesian product of the sequences of the even numbers and that of the odd numbers treated separately. Thus:
n!n!
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add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
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since there are 2n numbers so there are n even numbers and n odd numbers
So all the n even numbers can be arranged at even places in n! ways and the odd numbers in n! ways at odd places
So the possible ways to arrange them is ( n! x n! ) ways.
$endgroup$
add a comment |
$begingroup$
since there are 2n numbers so there are n even numbers and n odd numbers
So all the n even numbers can be arranged at even places in n! ways and the odd numbers in n! ways at odd places
So the possible ways to arrange them is ( n! x n! ) ways.
$endgroup$
add a comment |
$begingroup$
since there are 2n numbers so there are n even numbers and n odd numbers
So all the n even numbers can be arranged at even places in n! ways and the odd numbers in n! ways at odd places
So the possible ways to arrange them is ( n! x n! ) ways.
$endgroup$
since there are 2n numbers so there are n even numbers and n odd numbers
So all the n even numbers can be arranged at even places in n! ways and the odd numbers in n! ways at odd places
So the possible ways to arrange them is ( n! x n! ) ways.
answered Jan 23 at 10:33
cognitivecognitive
264
264
add a comment |
add a comment |
$begingroup$
If all the even numbers are put on the even places, only the odd places are left for the odd numbers. Then the set of possibilities is the cartesian product of the sequences of the even numbers and that of the odd numbers treated separately. Thus:
n!n!
$endgroup$
add a comment |
$begingroup$
If all the even numbers are put on the even places, only the odd places are left for the odd numbers. Then the set of possibilities is the cartesian product of the sequences of the even numbers and that of the odd numbers treated separately. Thus:
n!n!
$endgroup$
add a comment |
$begingroup$
If all the even numbers are put on the even places, only the odd places are left for the odd numbers. Then the set of possibilities is the cartesian product of the sequences of the even numbers and that of the odd numbers treated separately. Thus:
n!n!
$endgroup$
If all the even numbers are put on the even places, only the odd places are left for the odd numbers. Then the set of possibilities is the cartesian product of the sequences of the even numbers and that of the odd numbers treated separately. Thus:
n!n!
answered Jan 23 at 10:31
ternaryternary
61
61
add a comment |
add a comment |
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You can first populate the even numbers. So that's the same as asking, "in how many ways can you order the even numbers between 1 and $2n$". And after that you can consider the odd numbers (put them to their places).
$endgroup$
– Matti P.
Jan 23 at 10:31
$begingroup$
Welcome to Math.SE. Take a look at How to ask a good question at Math.SE. To avoid downvotes and closing you should add your own efforts to the question, and tell us where you got stuck.
$endgroup$
– drhab
Jan 23 at 10:48