Call them up and ask what topics the students have covered in term 2 and 3 and focus on those topics. A majority of the questions will come from there.
I recommend that you go to Sigma for Physics and Ace for Chemistry as they provide a better range of questions especially for exams. Also you do not need economics tutoring in year 11. Instead I suggest you put in the time to find questions online and just work through them and ask your school...
Notes on Topic 3 with the Tom Dixson, "The Market Economy" textbook in reference.
Correction
The law of demand
When the price of an item decreases, individuals tend to purchase more of that product as it is cheaper in comparison to other products and it is more affordable. Not increases.
Personally, I wouldn't recommend that you take Physics without any form of year 11 maths as some topics do get quite complex in terms maths so it could be beneficial to have some level of maths!