# Simplyfing this factorial

1. Dec 9, 2008

### Flappy

1. The problem statement, all variables and given/known data
$$\frac{(kn)!}{(kn+k)!}$$

I was thinking:

(kn)! = 1*2*3......(kn)
(kn+k)! = 1*2*3......(kn)(kn+k)

and I would be left with 1/kn+k

But my book has the answer as:
$$\frac{1}{(kn+k)(kn+k-1)....(kn+1)}$$

How can I arrive to that?

2. Dec 9, 2008

### mutton

There are k numbers between kn and kn + k, not just one.