This fully-solved book has been developed exactly to suit the need of the CAT aspirants. The objective of this textbook is to test the skill of the candidate in applying the concept and logic in solving problems in Quantitative ability section. The USP of the book is that each chapter opens with a self-diagnostic test with analysis so that each aspirant can self-assess one's level and it also guides him the tactics for preparation for that chapter. Main text has been designed with CTP technique (Concept Through Problem) where each concept/theorem/rule has been explained with the help of an illustrated problem following it. CTP enables the reader to master over the concept and to learn as how to apply this in solving a problem in CAT.