Karl wants to custom order 4 collars for his 4 unique cats A
 Karl wants to custom order 4 collars for his 4 unique cats. A custom ordered collar is tailor fitted to a pet and comes in a choice of 9 different colors. How many selections of collars for the 4 cats are possible if repetitions of colors are allowed?
  Karl wants to custom order 4 collars for his 4 unique cats. A custom ordered collar is tailor fitted to a pet and comes in a choice of 9 different colors. How many selections of collars for the 4 cats are possible if repetitions of colors are allowed?
Solution
4 collars for 4 unique cats.
There are 9 different colours.
First cat can have any of the 9 colours = 9 ways
SEcond also has 9 choices, hence total ways
= 9x9x9x9 = 6561 ways.

