HELP!!! PLEASE! Samantha received 6 dolls for her birthday. She plans to take two of them with her to grandma’s house. How many combinations of 2 dolls from the group of 6 could she take with her?

Question

anonymous · Answer

Do you know nCr? I think that's what you're supposed to use.

anonymous · Answer

I do not know what that is

anonymous · Answer

The binomial coefficient? Pascal's triangle?

shamil98 · Answer

x + y + z + n + k + h
let's use variables
how many different groups can you get from this?
xy yz zn nk kh
xz yn zk nh
xn yk zh
xk yh
xk

shamil98 · Answer

5 + 4 + 3 + 2 + 1 = 15

wolf1728 · Answer

The formula for selecting k objects from n objects is
combinations = n! /(k! * (n-k)!
combinations = 6*5*4*3*2*1 / 2! * (6-2)!
combinations = 6*5*4*3*2*1 / 2 * 4 * 3 * 2 * 1
=6 * 5 / 2 = 15

shamil98 · Answer

Yes, you can use that as well, I just thought a simple algebraic example would be easier. But my method is not that efficient when it comes to larger values of n.

shamil98 · Answer

Which is why one would use the formula wolf put out.

wolf1728 · Answer

That's the reason I showed it.  (not to upstage anyone)
Also, if the teacher wants an answer using a formula there it is.
:-)