Here's the question you clicked on:
Wolfboy
Aysha has 8 pictures to hang over her couch. She wants to hang only 3 of them. Find how many ways she can choose the 3 pictures from the 8
8c3 if order doesn't matter.
Are you familiar with Pascal's Triange?
u kno wat 8p3 is?
I'm pretty sure this is a combination and not a permutation.
yup that's a combination nd it's 8c3
Can use either Pascal's Triangle or the formula with factorials. For n=8, probably better off using the formula.
nCx = n!/(x!(n-x)!) I think that's it. I'm just pulling it from memory, so I might have it mixed up with the other one, but it looks right.
ok so how do we use this to make our equation. And sorry for the slowness i went surfing yesterday and i am still really tiered.
A quick drawing of Pascal's Triangle shows it's 56, and 8!(3!(8-3)!) = the same.
Do you know how to write out a factorial?
uh i probably do but dont remember can you show me again?
While I do that, do an internet search for "Pascal's Triangle." - It's useful not only for combinations, but also for finding the coefficients of an expanded power of a binomial.
n! = n*(n-1)*(n-2)*...*1 e.g. 8! = 8*7*6*5*4*3*2*1 dividing factorials is easy because so many common factors cancel out. e.g. 8!/3! = 8*7*6*5*4
Thanks for all of your help @CliffSedge