The question
What is the maximum number of O.W.L. classes you can take at Hogwarts?
Seems to be almost entirely a duplicate of
How did Bill and Percy get 12 OWLs?
Which is why I closed it as a dupe. So why has it been reopened?
The question
What is the maximum number of O.W.L. classes you can take at Hogwarts?
Seems to be almost entirely a duplicate of
How did Bill and Percy get 12 OWLs?
Which is why I closed it as a dupe. So why has it been reopened?
The questions are similar but they are not duplicates.
The first (older) question focuses specifically on how two specific students managed to take a specific number of classes in a semester, and if they did or did not need time turner help to do so.
The second question starts with the premise that you have no special magical help; what is the maximum number of classes you could take. It's possible that the answers are the same: that Bill and Percy took as many as possible. But it may be different. The class schedule may allow more, or it may be that it's not even possible to take 12 and they had to use magical help.
There is a lot of overlap, but far less than other questions that have been judged not-duplicates, given that the answers may or may not be the same.