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The number of ways to choose 4 items from 28 items is equal to
= = = = 20475. ANSWER
It is the number of combinations of 28 items taken 4 at a time.
Usually, for a student who only start studying this subject, it is difficult to understand the meaning of these words.
In simple terms, is the number of all different 4-element subsets of the given set of 28 elements.
Notice that the order of 4 people in the committee IS NOT IMPORTANT (does not matter) in this problem.
Solved.
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This problem is on COMBINATIONS,
and it is a typical and basic problem on combinations.
Usually, such problems are very first to get familiar with the subject.
On Combinations, see introductory lessons
- Introduction to Combinations
- PROOF of the formula on the number of Combinations
- Problems on Combinations
- OVERVIEW of lessons on Permutations and Combinations
in this site.
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.