Answer:
n = 8
Step-by-step explanation:
[tex]C(n,r)=\frac{n!}{(n-r)!r!}[/tex]
[tex]C(n,5)=\frac{n!}{(n-5)!5!}=56[/tex]
[tex]n(n-1)(n-2)(n-3)(n-4)=56(5!)[/tex]
[tex]n(n-1)(n-2)(n-3)(n-4)=6720[/tex]
[tex]n=8[/tex]
