Determine the number of its n-combinations

Thread starter Jrb599
Start date Jan 27, 2008

AI Thread Summary

The discussion focuses on determining the number of n-combinations from the multiset {n*a, n*b, 1, 2, 3,..., n+1}, which has a size of 3n + 1. A participant clarifies that for n=2, the multiset contains seven elements, confirming the size as 3n + 1 rather than n + 3. This resolution leads to the conclusion that the initial confusion about the size has been addressed. The thread concludes with a question about its potential deletion, indicating a desire for clarity on the forum's practices. The topic emphasizes understanding combinations in multisets effectively.

Jan 27, 2008

Jrb599

Consider the multiset {n*a, n*b, 1, 2 , 3,..., n+1} of size 3n + 1. Determine the number of its n-combinations.

I'm stuck on this one, any help would great.

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Jan 27, 2008

EnumaElish

Science Advisor

How is its size 3n+1 and not n+3?

Jan 27, 2008

Jrb599

Consider the case n=2

you get

(a,a,b,b 1,2,3) which gives you 7 elements

not 5, so 3n + 1 holds.

Jan 28, 2008

Jrb599

PRoblem solved, will this thread be deleted?

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