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![. The probability that two specified letters will be placed in the correct envelopes is 1[n(n – 1)]. The
probability that none of the othern – 2 letters will then be placed in the correct envelopes is qn-2.
Therefore, the probability that only the two specified letters, and no other letters, will be placed
in the correct envelopes is
1
-¶n-2. It follows that the probability that exactly two of the n
п(п — 1)
letters will be placed in the correct envelopes, without specifying which pair will be correctly placed,](https://content.bartleby.com/qna-images/question/8b0050e1-8a86-497b-9cc6-b844a5887701/b0f48d32-d6e8-4cce-9f39-f684fd591255/0v54w8k_processed.jpeg)
