How do you evaluate 8C3?

1 Answer
Aug 3, 2016

""_8C_3=568C3=56.

Explanation:

We know that, ""_nC_r=(n!)/{(n-r)!*r!}nCr=n!(nr)!r!

With, n=8, r=3, ((n-r)!)=5!n=8,r=3,((nr)!)=5!

So, ""_8C_3=(8!)/(5!*3!)=(cancel(5!)*6*7*8)/(cancel5!*3!)

=(6*7*8)/(1*2*3)=56.