How many ways can Ismail arrange four different textbooks on the shelf in his locker?

1 Answer
Oct 23, 2016

Answer:

#4! =24#

Explanation:

There are #4# different choices for the first book, but once that one is in place, there are #3# choices for the second, two for the third and then only 1 book remains to be placed on the shelf last.
This assumes that the books are all different.

The number of possible arrangements is #4xx3xx2xx1 = 24#

This is called '4 factorial' and has the symbol #4!#