SOLUTION: There are nine female board members and twenty-one male board members. How many ways are there to make a committee of twelve board members if exactly two must be female? Dete

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Question 1136801: There are nine female board members and twenty-one male board members.
How many ways are there to make a committee of twelve board members if exactly two must be female?
Determine the probability of selecting a committee of twelve board members where exactly two of the members were female. Write your answer as a decimal, rounded to the nearest thousandth.

Answer by ikleyn(52777) About Me  (Show Source):
You can put this solution on YOUR website!
.
There are nine female board members and twenty-one male board members.
(a) How many ways are there to make a committee of twelve board members if exactly two must be female?
(b) Determine the probability of selecting a committee of twelve board members where exactly two of the members were female.
Write your answer as a decimal, rounded to the nearest thousandth.
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(a)  You can select 2 females of 9 females by  C%5B9%5D%5E2 = %289%2A8%29%2F2 = 36 ways.


     You can select 12-2 = 10 males of 21 males by  C%5B21%5D%5E10 =  = 1279935820800%0D%0A%2F3628800 ways = 352716 ways.


     The answer to question (a) is the product of these numbers


     C%5B9%5D%5E2 . C%5B21%5D%5E10 = 36 * 352716 = 12697776 ways.


(b)  To answer question (b), you need to divide the answer to question (a) by the number of all combinations 
     of 21 items taken 12 at a time  C%5B21%5D%5E12 :


     P = %28C%5B9%5D%5E2+%2A+C%5B21%5D%5E10%29%2F+C%5B21%5D%5E12 = 12697776%2FC%5B21%5D%5E12.


I leave it to you to calculate the number C%5B21%5D%5E12 and to complete this assignment. It is just pure mechanical work.

Happy calculations !

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On Combinations,  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".


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.