Combination with repetition

by **Guest** Fri Aug 08, 2008 1:22 pm

Hi,

Does GMAT cover combinations with repetition such that the number of combinations = ((n+r-1)!)/((r!*(n-1)!)) ? If yes then could you kindly show me an example and how do I identify such a problem? Thanks

So three thing
1) Does GMAT cover this
2) If yes please gimme an example
3) How do I identify such a problem

by **RonPurewal** Wed Sep 17, 2008 4:38 am

1.
i have never seen this topic covered on any sort of official problem, at least not in a context that would require that formula.
i would bet a fairly large sum of money that, if you were to encounter a problem featuring these sorts of combinations, the number of combinations would be small enough so that you could simply list all of them.

2, 3.
http://en.wikipedia.org/wiki/Combinator ... epetitions