I actually asked the same question a few weeks back... didn't really get a straight answer in here.
But since then I started reading a bitmore... and It seems like both formats are possible. CFAI I believe mentions that they're trying to follow market covention by showing AUD:USD format.. But I don't think that means that AUD/USD format can't be on the exam.
What I do when I do any question is.. I convert any AUD/USD to the other format.
Sorry that I don't have a straight forward answer for you
Hey, that helps man. I like your answer no matter what.
Even I do the same: I convert it to the market convention. It's very easy to caculate the cross rates particularly then. I don't need a triangle. And what the heck is schweser doing by some stupid rule: up the bid, down the ask. That kinda sucks. Making things complicated.