If you are appearing for admission to Bachelor's courses, then the entrance examination is based at level 12th. You will be tested on your knowledge on General English, Economics and Statistics and Mathematics. General English has a weightage of 20%, and the rest 2 have 40% weightage each.
Under English section, you need to prepare for Grammar, Synonyms, Antonyms, sentence completion and Verbal ability. In Verbal Ability session, command on your English, Grammar, Vocabulary, Understanding of the given paragraph are of more importance. Reading English NewsPaper will also help you in your preparation. You will need a lot of reading to help you in the comprehension section. You will need speed to help you in this section and you can achieve that only by thorough practise and reading.
Word Power Made Easy (by Norman Lewis)
This is the go-to book to improve your vocabulary. It is not a book to be read but a book to work with daily to enrich your vocabulary.

High School Grammar and Composition( by Wren and Martin)
It is a very good book for people who want to improve their grammar skills. It helps to understand and conceptualise different aspects of grammar and it is a must have book for anyone with poor grasp on verbal ability or who wants to make up with the basics of English.
In Mathematics section again you have to prepared for 21th level questions. You should concentrate on topics like Integrals/Integration, Vector Algebra, Relations and Functions. Knowledge over application of Integrals, differential equations, increasing and decreasing functions.
From Economics, microeconomics chapters like Indifference curve, budget line, Consumer equilibrium are important. You also need to learn about Oligopoly and Monopoly. PPC, Cost and utility are important topics. National income, MPC and MPS and questions regarding Money and Banking and Macro economics are to be read thoroughly.
Under Statistics Section, Standard deviation, data representation, sampling are important topics. Mean median mode, quartile deviation and mean deviation formula are important and not to be missed as well.
For Mathematics, Economics and Statistics, you should stick to NCERT books. This should help you prepare well and score good. There are books for entrance exam in the market from various publishers as well and you can give them a try. But sticking to NCERT books is good enough.

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