cash and carry CFAI EOCs

first, gold, understand, practice, problems

I’m having trouble really understanding cash and carry arbitrage, and it’s so far the only question on the 6 CFAI and Schweser practice exams that really had me stuck for even getting started. My approach to small topics like this is to forget about trying to understand at this point, and figure out a systematic way to memorize the process in hopes of getting half points.
So I went back to Chapter 38 and did the practice problems. The first one is about gold cash and carry, and asks for the profits on entering with and without loaning. The net position at t=0 is nil, there is no net investment since the long spot is funded with a loan at rf.
The second question seems to be asking the same thing, except in that case, the answer has a net investment of 300 at t=0. I can’t find the distinction in the question as to when you would have no net investment and when you would have a net investment. There must be a key word that I am missing.
So in general, with cash-and-carry, you would short the forward, long the spot (and possibly lease out) and borrow at rf to purchase the long. However, in some cases, there is no borrowing, and that is the distinction I can’t figure out.
If anyone has this figured out, I’d appreciate some tips!