There are 11! different ways in which the birthstones can be arranged.
The total number of combinations is given by the product between the numbers of options for each position.
Then for 12 elements, there are 12! possible permutations.
Now we also need to take in account that there are 12 possible first positions to start counting (because there is no defined start and end for the birthstones) then we need to divide by 12.
There are:
C = 12!/12 = 11!
combinations.
If you want to learn more about combinations:
https://brainly.com/question/11732255
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