PLEASE HELP Probability / Permutations

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PLEASE HELP Probability / Permutations

by gmatpup » Wed Jan 04, 2012 7:14 am
Hi all,

I find that I am having difficulty understanding how to do Probability and Permutation problems. Can anyone please describe/explain how to go about doing any of these problems? Are there any tips?

I keep trying to do them but I think I need a solid explanation as I obviously cannot teach myself :(

Thank you so much!!
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by chieftang » Wed Jan 04, 2012 9:40 am
Please see the Combinatorics Notes linked in my signature, for a high level overview.

I've also heard very good things about the Veritas Probability & Combinatorics guide.

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by pemdas » Wed Jan 04, 2012 10:32 am
you have to look into counting primarily
then understand what is EVENT and OUTCOME, the differences between these two
then switch to Independence/Dependence of EVENTs and understand Mutually Exhaustive EVENTs
then you need to understand that combination is just the COMBINATION (as worded here) of one or more SUB-SETS within a SET
then you will look into MGMAT Word Translation guide and meticulously do their letter branching by hand and understand (though remember here counting too) what is combination
then you are ready to go for permutation or an ordered combination


BTW, when done with combination you will understand that EVENT is relevant to not only probability but combination theory too. As such consecutive branching (or combined sets) is an element of one EVENT. The same way it works with counting: all branches taken together should multiply and increase into one big branch to continue combination through with other possibilities (different sub-sets linked)
g.l.
gmatpup wrote:Hi all,

I find that I am having difficulty understanding how to do Probability and Permutation problems. Can anyone please describe/explain how to go about doing any of these problems? Are there any tips?

I keep trying to do them but I think I need a solid explanation as I obviously cannot teach myself :(

Thank you so much!!
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