SOLUTION: Determine the number of permutations 20 things, taken four(4) at a time

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Question 1193864: Determine the number of permutations 20 things, taken four(4) at a time
Answer by ikleyn(52756) About Me  (Show Source):
You can put this solution on YOUR website!
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It is  20*19*18*17 = use your calculator = 116280.      ANSWER

Solved and explained.

To memorize,  it is the product of  4  (four)  consecutive integer numbers in descending order,  starting from the number  20.

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On  Permutations,  see introductory lessons
    - Introduction to Permutations
    - PROOF of the formula on the number of Permutations
    - Simple and simplest problems on permutations
    - Special type permutations problems (*)
in this site,  especially lesson marked  (*)  in the list as the nearest to your problem.

Also,  you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic  "Combinatorics: Combinations and permutations".


Save the link to this textbook together with its description

Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson

into your archive and use when it is needed.