Frustrated maths fans were seething at this bizarre question - but the teacher who wrote it has hit back.
The trick question about Beethoven's 9th Symphony was trending on Twitter after an alarmed person posted it.
"An orchestra of 120 players takes 40 minutes to play Beethoven's 9th symphony," the question goes. "How long would it take for 60 players to play the symphony?"
The incensed tweeter wrote: "That's not how it works. That's not how any of this works."
Thousands of commenters quickly jumped on board, saying the question makes no sense - as the number of players in the orchestra wouldn't make any difference to the length of the classic.
One tweeter wrote: "I'm so angry right now, this has ruined my whole day."
"That's like saying 'It takes 9 months for a woman to have a baby, how long would it take for 2 women to have a baby?'" posted another.
"Two options, it is a logic trap question or the question writer is an imbecile," one tweeter wrote.
Classical music fans were also confused because the Beethoven composition is supposed to last around 70 minutes.
However, original writer Claire Longmoor - a teacher from Nottingham in the UK - discovered her work being shared on Twitter, and posted a response.
The brainbox put together a selection of example questions with relationships in direct and inverse proportion over 10 years ago.
She said it was a trick question to keep students alert while making their way through the worksheet and even posted a copy of the original test.