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Author Topic: A probability question -- need help  (Read 6058 times)

CuteBird

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A probability question -- need help
« on: January 15, 2011, 10:08:33 PM »
Hello, I need help for the following question:

There are 9 different boxes lined up. There are 5 same balls.
You put these 5 balls into those 9 boxes.
A box may have more than one ball, or no ball at all.
How many ways are there to put the balls into the boxes?

I don't know the answer.

Thanks in advance!
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yongcheng3315

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Re: A probability question -- need help
« Reply #1 on: January 16, 2011, 04:51:47 PM »
See Twenty Problem Solving Skills Book 1 Chapter 8. It is the nonegative integer solutions to the equation:

x1+x2+..x9 =5

Also Chapter 15 Balls and Boxes deals with this kind of problems.
« Last Edit: January 16, 2011, 04:56:37 PM by Andover 2011 »
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CuteBird

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Re: A probability question -- need help
« Reply #2 on: January 16, 2011, 05:55:23 PM »
Thank you very much! I have the book, but have not read that far yet.
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