The BT YG file is a question bank containing 500 q each on P,C,M.The YG file for the current obj pattern is a little over-hyped version as the quality of Q's is not the brain-racking ones (more of the tricky kind).But if you take it as an additional resource alongwith the BMAT series it will be better. (It could be better if you could lay your hands upon the earlier subj version.)