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?
Is blank paper allowed for the BCG online case?
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.
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.
Related BootCamp article(s)
Which companies are currently using written tests ?
All major firms like McKinsey, BCG and Bain use tests to assess a candidate's analytical skills. However the design of those tests can differ a lot.