State rankings for Business Studies is usually the Top 20 people in the state (this year out of approx 19,000 people).
To get a state rank, you must: get a High Band 6 (usually between 96-100, often in decimal points when divided for 1 unit) AND be ranked first/close to it in your school.
Depending on how your you went, you might just be in that top 20. Remember though, that means you're in the top 0.1% of the state, most of these people topping their school which would be a Top 10 School.
To get 1st in state, you MUST get the highest HSC Exam mark and BE RANKED 1st internally. Pymble's Lady College have had this covered for awhile.