Permutations and Combinations 3 Question 9
9. Words of length 10 are formed using the letters A, B, C, D, E, F, G, H, I, J. Let be the number of such words where no letter is repeated; and let be the number of such words where exactly one letter is repeated twice and no other letter is repeated. Then,
(2017 Adv.)
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Answer:
Correct Answer: 9. (5)
Solution:
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