Question 1100741: In how many ways can you place 9 different books on a shelf if there is space for only 5 books? Answer by KMST(5328) (Show Source):
You can put this solution on YOUR website! There are 9 choices for the book to place at the left end of the shelf.
Whatever book you choose,
there are 9-1=8 books to choose for the next place on the shelf.
So far, you had different choices.
You keep choosing what book to place on the shelf to the right of the books already on the shelf.
Eventually, there are 5 books on the shelf and 9-5=4 books that were left.
The total number of different possible ways to place 5 of those 9 books on the shelf is .
