Question

David on all 7 books and the Harry Potter series and how many different orders can he place all of them on top shelf of his bookshelf

Answer 1

We are going to use factorial

Now, we have seven different books to be placed on shelf

$7!\text{ = 7}\times6\times5\times4\times3\times2\times1\text{ = }5040$

Hence, David can place all the 7 books on top shelf of his bookshelf​ in 5040 different orders.