This shouldn't be too hard...
So I have an exam tomorrow, I would like to study as little as possible for it, and I would like you to tell me what are my chances of succeeding:
There are 9 topics in the module.
There are 6 questions in the exam.
The exam is divided into two sections (3 questions in each section).
One must answer 1 question per section.
If one studies 5 topics out of the 9, what are the chances that he won't be able to answer any questions in one section. (i.e. what are the chances of failure).