Is it allowed to take notes during the test or we are supposed to keep previous answers in mind and/or come back to old questions for interdependent questions?
I took the BCG Potential Test last week. The answer to your question is yes, you are allowed to have a blank paper during the test. Specifically, you are left in a room with a computer, pen and stack of white papers. Depending on your office (you should ask) you might be allowed to use a calculator or not. Let me know if you have any other further questions about the test.
(editiert)
Any tips about the test or the BCG interview in general? Which country are you applying in? Congrats on getting the interview!! — am 2. Okt 2018
Yes, you can. For reference, I haven't heard of any tests where you aren't allowed to use pen and paper to do calculations/take notes - you can assume this is always a given. Less of a given is whether you can use calculators or not.
Good luck!
Alessandro
BCG Online Case Secrets von Francesco 
