I have never done Business Studies before, but let me tell you a few secrets;
Basically, your teacher will always ask you to revise hard and study past exam questions thoroughly.
In effect, yes, you need to do that - but hell no you don't need to be worried. Most likely you will walk in to an exam, get a question and you will be like - Ohh wait, thats an easy question - I know the knowledge already omg what am I thinking.
Basically Im just saying don't worry because the questions you will get you should know how to answer unless your teacher has taught you wrong.
Secondly - Should you revise with a text book, don't revise the majority of the book in a day. You are REQUIRED to spread the book revision out daily otherwise you eventually forget it.
So daily - Read some, store it, use it.