Onde, exatamente, diz que ela conseguiu doze O.W.L.s?
Isto é o que a minha cópia de Half-Blood Prince diz:
“Oh, come off it,” said Ron, striding over to [Hermione] and whipping her results out of her hand. “Yep – nine “Outstandings” and one “Exceeds Expectations” in Defence Against the Dark Arts.” He looked down at her, half-amused, half-exasperated. “You’re actually disappointed, aren’t you?”
Isso faz dez OWLs, o que é totalmente consistente com a lista de assuntos conhecidos.
Parece que eu falei cedo demais. Estou usando uma edição britânica recente do livro, mas outras impressões (incluindo os OPs - ver comentários) não estão de acordo. O artigo da HP Wiki sobre os estados de O.W.L. :
In early editions of Harry Potter and the Half-Blood Prince, Hermione Granger is said to receive eleven O.W.L.s, scoring ten O's and one E. However, after the events of Harry Potter and the Prisoner of Azkaban, Hermione shrunk her class load from twelve subjects to ten, dropping both Divination and Muggle Studies. This was corrected in the Scholastic edition, where Ron instead states the she received nine O's and one E, giving her a total of ten O.W.L.s.
Esta versão dos eventos é apoiada pelo seguinte artigo:
Publishers have been forced to correct an error in one of JK Rowling's Harry Potter blockbusters.
The hardback edition of the sixth instalment of the schoolboy wizard's adventures, Harry Potter and the Half-Blood Prince, said that swotty Hermione Granger had scooped 11 top results in her Ordinary Wizarding Levels (OWLs). But hawk-eyed readers spotted that in the previous book, Harry Potter and the Order of the Phoenix, she had only taken 10 subjects.
Publishers quickly fixed the discrepancy in the next edition, downgrading her results from one "Exceeds Expectations" and ten "Outstanding" grades to nine "Outstandings" and one "Exceeds Expectations".
The change in the Harry Potter books was reported on fan site www.mugglenet.com.
A spokeswoman for publishers Bloomsbury said that the error had been spotted last year and quickly fixed.
"In book six it said 11 and book five it said 10," she explained.
"It was corrected immediately."
("Potter Book's OWL-ing Error Fixed", The Yorkshire Post, 2nd September 2006).
Isso, por sua vez, parece consistente com a minha experiência e com a do OP. Giz este até a matemática desonesta de JKR.