http://gateoverflow.in/questions/mathematics/discrete-mathematics/combinatory?sort=featured
Course Exercises
and
6. http://www.mediafire.com/file/5po7en4b522o4cx/Problems_In_Calculus_Of_One_Variable_-_I_A_Maron.djvu/file
8.https://www.mediafire.com/folder/gp6z7khjzyl8d/gate_materials?fbclid=IwAR3gGmo1bylfItTM4_8i_IHNhxS_WqEUSwbsP2W2M8TrLnlf_-nTzklJp6w#jm21b3m5rioss