Question

You have eight books to place on a shelf, but you only have room for five of them. how many ways can you arrange books on this shelf?

Answer 1

Basically you have to choose five books out of eight first before arranging them. So how do you do that?

Answer 2

I don't know I think arrange them but how?

Answer 3

@imqwerty @pooja195 @Prathamesh_M

Answer 4

To choose m objects out of n you use the expression:
\[mCn=\frac{ m! }{ n!(m-n)! }\]

Answer 5

So once you're done with that, you have to find the number of ways in which you can arrange those five books which is basically 5!.

Answer 6

Then you multiply both numbers to get the final answer.