Answer:
720 ways
Explanation:
If you are arranging your dog's collars on a 6 hanger coat rack on the wall and if she has six collars, there are 720 ways to arrange them.
Factorial of 6 = 720
For example it could look something like,
Collar 1, Collar 2, Collar 3, Collar 4, Collar 3, Collar 2, Collar 1, and so on.