The number of ways that 15 books can be arranged on a shelf is the same as the number of permutations of 15 things taken 15 at a time. This is 15 factorial, or 15!, and is 1,307,674,368,000.
it depends on the shelf of course
Slowly and methodically, I arranged the books on the shelf.
using the Dewey decimal system
120. You do 5*4*3*2*1=120. you multiply the number that you are given for example how many times can books 3 be arranged on a shelf you multiply 3*2*1=6 that is your answer
The number of permutations of five things taken five at a time is five factorial, or 120.
The answer depends on how many books on each subject there are.
6! = 1 x 2 x 3 x 4 x 5 x 6.