WE WERE TAUGHT VERY HIGH LEVEL COMBINATORICS AND BINOMIAL THEOREM IN XI WHICH CANNOT BE FOUND IN ANY IIT GUIDE. CAN ANY ONE SUGGEST A GOOD BOOK GOR COMBINATORICS???

Dear Srajan,
Mathematics Olympiad of Arihant
Or Pre college Mathematics
Or IIT Objective mathematics RD SHARMA.
Regards.

algebra part 1-arihant

objective mathematics -r.d. sharma

indian national mathematics olympiad-rajiv manocha-arihant publication

Skills in Mathematic for iit jee (Arihant) is a gud book

You can refer to the book A PATH TO COMBINATORICS FOR UNDER-GRADUATES written by TITU ANDREESCU and ZUMING FENG.