CAT has question relates to reasoning..n bds studenta had left maths from 7 yr..is it possible for bds student to compete with iitaian

Yes definitely you can clear Mathematics topics like Quantitative aptitude and Data Interpretation section of CAT even from Medical background as we have observed even MBBS students do go for MBA via CAT.
Secondly witn proper coaching and indepth practice you can compete top level IIT Grads as well.
All it requires is sfrong fundamental and passion to work jard in weak zones and with suucessive mock exams you can surely peeform well in all sections irrespective of backgrounds.