"Tagged" is not the best term so I will edit. Basically, there is a counter for answers against questions. My proposal would mean that if a question has been categorised as a duplicate then it should share the counter from the original question.

Okay. Thanks. I've edited the original post along those lines.

I was thinking more that the backend of Stack Overflow should take the duplicate question out of the list of unanswered questions if and only if the conditions I mentioned are met.