For Physics 1 person got a band 6 and for business 3 people got a band 6
In that case it might be difficult for you to get a band 6 in either (but still anything is possible). Do you know roughly the marks of last yrs cohorts? In which subject was the average higher?
I'm personally heavily biased towards physics because I think it's easier to drastically improve your marks in and it scales and aligns better. That is, lets say you got 76 in HSC, your mark will become 86 and then, after, it will scale better than other subjects at 86.
But for business if you need 81 to get aligned to 86 and after that it will scale less.
But it depends because what if your cohort is bad at physics and you get raw 81 in business and only 65 in physics. In that case business will be better.
I hope this makes sense because its a lot to understand.