Using the permutation formula, it is found that the probability that the CDs end up in alphabetical order is:
[tex]p = \frac{1}{8,204,716,800}[/tex]
For this problem, the order in which the CDs are chosen is important, hence the permutation formula is used to solve this question.
What is the permutation formula?
The number of possible permutations of x elements from a set of n elements is given by:
[tex]P_{(n,x)} = \frac{n!}{(n-x)!}[/tex]
8 CDs are chosen from a set of 21, hence the number of ways they can be chosen is:
[tex]P_{(21,8)} = \frac{21!}{13!} = 8204716800[/tex]
Only one arrangement is in alphabetical order, hence the probability is:
[tex]p = \frac{1}{8,204,716,800}[/tex]
More can be learned about the permutation formula at https://brainly.com/question/25925367
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