This old question asks why Pesach and Sukkot last seven days.
This recent question asks why Pesach and Sukkot last seven days and (in contrast) Shavuot lasts only one.
What is site policy in this case?
Closing the old question as a duplicate seems pretty unfair and non-intuitive.
Closing the new question as a duplicate also seems to be wrong, as the old question is not asking for answers about Shavuot.
I believe there is some way for moderators to merge questions, but I'm not sure if that would be appropriate here either, as answers to the first question don't fully answer the second, and answers to the second are providing more information than was requested by the first.
Maybe the answer is simply to leave both questions as they are, with a note in the comments?