Question

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

Answer 1

8p3

Answer 2

8c3 if order doesn't matter.

Answer 3

Are you familiar with Pascal's Triange?

Answer 4

uh not realy

Answer 5

u kno wat 8p3 is?

Answer 6

not exactly

Answer 7

I'm pretty sure this is a combination and not a permutation.

Answer 8

yup that's a combination nd it's 8c3

Answer 9

Can use either Pascal's Triangle or the formula with factorials. For n=8, probably better off using the formula.

Answer 10

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.

Answer 11

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.

Answer 12

A quick drawing of Pascal's Triangle shows it's 56, and 8!(3!(8-3)!) = the same.

Answer 13

Do you know how to write out a factorial?

Answer 14

uh i probably do but dont remember can you show me again?

Answer 15

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.

Answer 16

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

Answer 17

Thanks for all of your help @CliffSedge