probability!!

Problem Solving — algebra and arithmetic (GMAT Focus Edition)
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probability!!

by marmar29 » Mon Mar 28, 2011 8:48 pm
hello
whilst googling the sites for marth
i found some explanation for probability whr he used 1 C 2 as for the coin
i guess 1 is prob. to get H OR T n 2 is the total
but C stands for wht ??
kindly tell me
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by vineeshp » Mon Mar 28, 2011 9:16 pm
Hi,

C stands for combination. from permutations and Combinations.

Basically in Combinations, the order of the items do not matter.

Typical example is
From a bag of 3 red balls and 4 white balls, in how many ways can 2 white balls be selected?

In the answers to this, when two white balls (W1 and W2) are selected. it does not matter if W1 or W2 was selected. in these cases, we call them combinations. 2 C 1 means from a set of 2 items, how many ways 1 items can be selected.

If you want to prepare for GMAT math, I found this to be a good site.
https://www.platinumgmat.com/gmat_study_guide/
Vineesh,
Just telling you what I know and think. I am not the expert. :)

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by VivianKerr » Tue Mar 29, 2011 1:31 pm
Vineeshp is correct. GMAT occasionally features permutation ad combination questions. They can be tricky, so it's good review these concepts thoroughly. Here are some links I suggest:

https://grockit.com/blog/gmat/2010/09/22 ... -counting/

https://www.beatthegmat.com/mba/2010/07/ ... bility-101 (this is an excellent 4-part series)

https://www.beatthegmat.com/mba/2010/10/ ... mbinations

Many students have posted difficult combination/permutation questions here, so you can search those and read through the explanations. Veritas also makes a good that focuses entirely on probability if you want to go further.

Good luck!
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