My integration services isnt one of my strongest points, so I just wondering how indepth your knowledge of SSIS would need to be, to cover the questions that you had to answer.
You definitely need to know the SSIS Transformations (Merge Join, Union All, etc.) and Tasks (Data Profiler, Execute Package, etc.) which you could learn from studying a book. You also need to know the SSIS structure of Control Flow versus Data Flow and which parts of the package are placed in each flow. In short, you should be able to design a moderately complex job from scratch before taking the test including the restartability and error handling features. Book learning will not be enough to answer all the SSIS questions correctly, but the test is evenly divided between SSIS, SSAS and SSRS so I assume it's only 33% of the score for the exam.
Do you know the CheckpointUsage options and what the colors red, green and blue indicate for precedence constraints? If you know these without research, then you have the depth of knowledge required for the exam.
I can't say much more than that without violating the NDA, but practice exams like those from Transcender will test you on the key SSIS topics. Good luck!