Sana, over the past 31 years, the syllabus has pretty much remained the same with no major changes. And so if you prepare for the next one week from the previous question papers, you can answer approximately 80% of the answers. But what you need to remember is that the question will not be asked the same way they were asked 31 years  back. The question might change while the answer might remain the same. So you need to understand the concept rather than memorising the answers. If you just go ahead and memorise the answer alone, if the question is twisted, you might end up being confused and inspite of knowing the correct answer, you might either skip it or answer it wrong. So utilise the time left and get the basics correct.