Respuesta :
The number of ways to choose k items out of n items is:
[tex]\frac{n!}{n!(n-k)!}[/tex]
Plug in n as 9 and k as 4, and that's the answer:
[tex]\frac{9!}{4!(9-4)!} = 9*8*7*6*5/5/4/3/2 = 126[/tex]
[tex]\frac{n!}{n!(n-k)!}[/tex]
Plug in n as 9 and k as 4, and that's the answer:
[tex]\frac{9!}{4!(9-4)!} = 9*8*7*6*5/5/4/3/2 = 126[/tex]