.
Let us solve more simple problems first:
1. In how many ways can you select 2 members among 11 faculty members?
Since the order is not important, there are = = 55 ways.
2. In how many ways can you select 5 students among 12 students?
Since the order is not important, there are = = 792 ways.
3. Now, the selections among these two groups are independent.
Hence, in all , you have 55*792 ways in your global problem.
These magic numbers are called the numbers of combinations of n things taken k at a time.
About combinations and about these numbers, see the 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".
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