::
I remember doing this question!
I always thought this question is a bit flawed, so I agree with your assessment that strictly speaking this question does not have enough information.
Additionally, the underlying fund fees may actually be completely different, as they are (presumably) a compilation of funds, and so applying a basic 20% margin to the aggregate profit will not be right way to do it “in the real world”.
I’ve sat for L1 but honestly don’t remember if the exam questions were this confusing – it was a blurry mess of a day. I can only imagine so since this is a CFAI question.
Just my two cents, hope it helps.