INCOSE's Certification Program generates the knowledge exam based on a blueprint generated with the help of our psychometric consultants. The blueprint is a list of topics we will test on (the learning objectives) and the number of questions each exam will have on those topics. All candidates take exams that are equivalently distributed across the learning objectives. We don't publish that distribution, but we do publish the learning objectives.
If you are studying for the INCOSE knowledge exam, it is a good idea to review the list of learning objectives. They can help guide your review of the INCOSE Systems Engineering Handbook (the sole source of content for the exam) to focus on the topics that will be tested.
You can find the learning objectives posted here