Reasoning- First take all possible permutations and then consider grp (a,b), c ,d.. get permutations for that and then subtract it from the from the set of all combinations
In this question, aa...a is a valid sequence (repetitions are allowed). Then, I don't think using permutations is a good approach. Let's try with n = 2, 4Pn - 3Pn does not give the correct answer.
2 comments:
Is it 4Pn - 3Pn
Reasoning- First take all possible permutations and then consider grp (a,b), c ,d.. get permutations for that and then subtract it from the
from the set of all combinations
In this question, aa...a is a valid sequence (repetitions are allowed). Then, I don't think using permutations is a good approach. Let's try with n = 2, 4Pn - 3Pn does not give the correct answer.
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