SOLUTION: There are 16 girls and 20 boys in a class. A team of 3 students is to be selected for preparing a science project from this class. How many ways can a two boys and a girl be select

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Question 1172653: There are 16 girls and 20 boys in a class. A team of 3 students is to be selected for preparing a science project from this class. How many ways can a two boys and a girl be selected from this class?
For this question, I’m assuming we need to use permutations since order counts (one girl, 2 boys). I have tried 36 and 3 because 16 plus 20 is 36. I’m having trouble coming up with the right solution.

Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

It is your mistake to think that the order does matter in this problem.


It DOES NOT:  the team (John,Martha,Peter) is THE SAME as the team (Peter,John,Martha).



Therefore, you should use COMBINATIONS.


You can select 2 different boys from 20 boys by  C%5B20%5D%5E2 = %2820%2A19%29%2F2 = 10*19 = 190 different ways.


You can select one girl from 16 girls by C%5B16%5D%5E1 = 16 different ways.


Since the selections in different (disjoint) categories are independent, the total number of different teams is the product

    
    C%5B20%5D%5E2 . C%5B16%5D%5E1 = 190*16 = 3040.    ANSWER

Solved.

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You REALLY NEED to learn the basic knowledge in Combinatorics.

For introductory lessons on permutations and combinations, see
    - Introduction to Permutations
    - PROOF of the formula on the number of Permutations
    - Simple and simplest problems on permutations

    - Introduction to Combinations
    - PROOF of the formula on the number of Combinations
    - Problems on Combinations

    - Miscellaneous problems on permutations, combinations and other combinatoric entities
    - Fundamental counting principle problems
    - Nice recreational problems on permutations

    - OVERVIEW of lessons on Permutations and Combinations
in this site.   //   I listed here the "introductory" lessons only . . .

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.