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Ok, so this might not be a permutation or combination but I'm curious as to what the answer is.

Question: There are 3 groups and 5 Objects in each group. How many combinations are there if your choosing one from each group?

Yes this is in reference to Call of Duty: Black Ops perks lol.

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Com'on, I am sure you can do it by yourself! Let's just count. How many possible objects from group 1? How many from group 2? How many from group 3? Now, what to do with these 3 numbers (addition, multiplication, ...) ? –  Djaian Nov 12 '10 at 15:45
    
I did it myself and got 125 just wanted to make sure... –  Gage Nov 12 '10 at 17:58

2 Answers 2

up vote 3 down vote accepted

You have five choices from the first group, times five from the second, times five from the third, for a total of 125 choices total. To see why this is the case, imagine writing out the possibilities:

1,1,1

1,1,2

1,1,3

1,1,4

1,1,5

1,2,1

...

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Thats what I thought, just wanted to know for sure. Thanks –  Gage Nov 12 '10 at 16:02

How many combinations are there if there is only one group? For each of those, how many ways can you choose from the second group? And the third? Multiplication is your friend.

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