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At a certain high school, the Prom Committee is going to choose new members.
There are 7 students from the Junior class and 6 students from the Senior class who are willing to be new members.
In how many ways can 4 new members be chosen if 2 or fewer must be from the Senior class?
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The solution to the problem is
N(2 students from the SR class) + N(1 student from the SR class) + N(0 students from the SR class) =
= + + = 15*21 + 6*35 + 1*35 = 560.
ANSWER. In 560 different ways.
Solved.
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This problem is to use COMBINATIONS and the Fundamental Counting Principle.
See introductory lessons
- Introduction to Combinations
- PROOF of the formula on the number of Combinations
- Problems on Combinations
- Fundamental counting principle problems
- 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.