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Formula Needed
Interesting...
If I use the formula you suggest "...combin(5,2) multiplied by combin(3,2)..." I end up with a value of 30. So, how do we end up with 15? Are we simply taking our total of 30 and dividing that by two due to the fact that we're pairing up the people? Thanx again. "Bill W" wrote: Take a look at the Help items for each of these functions - they probably explain the theory better than I can. Whether to use PERMUT or COMBIN depends on whether you need to distinguish between the partnership of (say) Purple and Blue and the partnership of Blue and Purple, and this may well depend upon the game they are playing. Re-reading your question I realise that you need to calculate the number of games that can be played by any two two-person partnerships from five players. This you can do manually and it is 15. You select two players (say Purple and Blue and work out how many more partnerships can be made with the remaining three players, which is three. You will get duplication by doing it manually and then need to delete the duplicates. Mathematically you are selecting any two players from five, and matching them with any two from the remaining three. If the order of the sets of two players is unimportant you use COMBIN. And the number of games is calculated using COMBIN(5,2) multiplied by COMBIN(3,2), because when the first two players have been paired, there are three remaining from which two are selected. This is 15, which is correct. If you are concerned about the order of the set of two players, then use PERMIT in both formulae, which gives 120. I'll let you check that manually! "Steven Sinclair" wrote: Okay. So if I use the PERMUT function, I get 20. If I use the COMBIN function, I get 10. Does that mean my answer would be 30? Thanx again. "Bill W" wrote: Steven, It depends whether you need to distniguish between the order of the players or not. The mathematical functions Permutation and Combine will caculate the number of ways in which any number of items can be put together in sets comprising a certain number of items, with Perm finding the number of ordered sets and Combine the total number of sets irrespective of order. They use the mathematical function "factorial" which is the product of a whole number (integer) and all the numbers less than it down to 1. So factorial 3 is 3x2x1=6, factorial 4 is 4x3x2x1=24, etc. Combine will divide the factorial of the number of items by the factorial of the number of sets. So 3 items combined in sets of 2 will give 3, and Perm will give 6, etc. These functions are available in Excel under the names PERMUT and COMBIN "Steven Sinclair" wrote: Here's what I have... Purple Blue Red Orange Green Each of the colors represent a player. Each of the players needs a partner. Each set of partners needs to play with another set of partners. Each player needs to play with a different partner against all other partners. All-in-all, we need to count how many games can be played with how many UNIQUE partners and UNIQUE opposing partners. I have no idea of even where to begin other than just writing everything out by hand on a piece of paper. Thanx. |
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