Question

Jered's parents are going to repaint their house. They need to select two colors to complete the job. If they previously narrowed their decision down to six colors, how many combinations of two can they choose from?


A. 12
B. 15
C. 30
D. 3

Answer 1

a or d

Answer 2

Neither.

Answer 3

i'm really thinking a

Answer 4

then it's c

Answer 5

No, not that either.

Answer 6

ok then i'm confused

Answer 7

nCr, that's what you're doing. n = total to choose from, r= number of items you take from the n

\(\Large\frac{n!}{(n-r)!r!}\)

Answer 8

how

Answer 9

n = 6, r=2, plug in and solve

Answer 10

@Agl202 if its not A, C, or D. Well of course its B

Answer 11

i gt 3 so like i said d

Answer 12

How did you get 3? @chycora
Remember that 6! = 6 x 5 x 4 x 3 x 2 x 1

Answer 13

so when i do that i get 720 that is nt even close to 15 so still don't get it

Answer 14

That's not the whole formula. Look u p there^ to see all of it.

Answer 15

\(\Large\frac{6!}{(6-2)!2!}\)

Answer 16

ok i did that wel watever i puting in b so thanx

Answer 17

you're welcome

Answer 18

\(\Large \frac{6!}{(6-2)!2!}\rightarrow \frac{720}{4!(2)}\rightarrow \frac{360}{24}\rightarrow \large 15\)