2-3 weeks (at most) for micro/macro each iirc
I just did economics this semester and know people who did economics last year (in high school), and the stuff that they knew got covered incredibly quickly (same timeline OzKo stated).
As everyone else has said, less than your first 4 weeks (of both introductory macro + micro)
I am actually going to sort of disagree with this, by speaking from my experience.
I did Prelim and HSC Economics. And I am now in my first semester of my first year of university. I just finished Microeconomics 1 (ECON1101), which is the first economics course you do. Here is the course outline for the subject -->
https://www.business.unsw.edu.au/Pr...ECON1101_Microeconomics_1_PartsA+B_S12015.pdf
As you will see on Page 12, nearly all the topics listed in the syllabus are topics that we give some sort of treatment in Year 11 and/or 12 Economics. In ECON1101, we examined production possibility curves, elasticity of demand & supply, price ceilings & floors, trade protection (tariffs, quotas), oligopoly, positive & negative externalities, free-riding (in respect to public goods) - these are ALL concepts/topics that are given a relatively good treatment in the Prelim and/or HSC syllabi. The only difference is the depth into which we delve, in regard to these topics. The teaching of it in university is more rigorous, more technical and more quantitative compared to what one would have experienced in high school economics.
So in a way, your original question of "how long it would typically take for universities to cover the Yr11-12 content?" sort of doesn't really have an answer. This may be for UNSW though, but I thought I'd just share this.