How do you know when to use "P" or "C" in Ordinary Maths??

user12 · 13-06-2010 11:13PM #1

Any clues??

Does one usualy come up in part B or C that we could tell the diff??

Lawliet · 13-06-2010 11:35PM

I don't know what you're talking about, which question is this in?

Zephyr91 · 13-06-2010 11:37PM

Lawliet wrote: »

I don't know what you're talking about, which question is this in?

Me neither. I didn't wanna reply in case I was missing out on something LOL

Oh Sheesh Yall Twas A Dream · 13-06-2010 11:41PM

http://mathforum.org/dr.math/faq/faq.comb.perm.html

Cyzrane · 13-06-2010 11:41PM

This is referring to probability. Question 6 on paper II.

To put it simply, nCr button is used when you are "choosing" or "selecting" certain elements from a set.
nPr is used when you are "arranging", or when the concept of order matters.

Hope this helps somewhat. It might also be good to know that in my experience nCr is used a lot more than nPr, mostly the "arranging" is done by simpler use of factorials.

pathway33 · 13-06-2010 11:45PM

C - Choosing

P - Positioning

freeze4real · 14-06-2010 12:03AM

Nah it doesn't help. How do you know which is which. How do you tell combinations from permutations.

How do you know when to use "P" or "C" in Ordinary Maths??

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