Pretty sure the answer is just “40 minutes” and it is a question to make someone think about what they are doing rather than automatically solve every task.
But it’s still wrong, though, as the 9th is about 70 minutes.
There’s even a myth saying that the 9th was the determinant for the length of the original CD.
IIRC the speed of the 9th symphony is somewhat controversial because what markings we have on original sheetmusic are significantly faster than it’s normally played.
Symphony music in general is going to vary a decent bit depending on what bpm(s) the conductor is choosing.
Any decent conductor is going to to vary the beat based on how long it takes for sound to fill the venue in question. Beethoven’s choices for the music halls in Vienna might have made sense then, but not so much today.
One of the things that’s always annoyed the conductors that I’ve worked with is that we always ignore the dynamics in his music. Beethoven’s markings are expressive, subtle. And we always play his stuff louder than indicated.
This is similar to something I assumed right before I had a long argument with a high school physics teacher. We ended up agreeing that he just didn’t really care.
Or 80 and it’s a question to learn extracting information
Like saying “let pi = 3” the point isn’t that pi is equal to 3. It’s that you can take that information and solve the rest of the expression
