Problem of Problem Curator

In a Online adaptive test there are problems of N difficulty levels ( 1 being the easiest and N being the hardest). Each difficulty level will have a certain pool of questions. A examinee will first be given a question from the pool of (N+1)/2 th difficulty level and based on his answer he’ll be promoted or demoted to next or previous level i.e. next he’ll get a question from pool of (current diff