Hello

You can easily crack IPM in 3 months.I was also an IPM aspirant and i cracked the written test in preparation of just 1 month but failed in further selection process.But if you don't Mathematics subject in your+2,it can affect your performance a bit.

So I am going to give you some tips to crack IPMAT in just 3 months,but you really need to work hard for that.You should give at least 5-6 hours of study daily.As IPMAT consist of three sections that is Quantitative Ability(Short Answer Questions),Quantitative Aptitude(MCQs) and Verbal Ability (MCQ).

Here is some tips for you-

• Join Coaching Classes - You can join coaching classes which will help you a lot.They give you guidance on how to crack it and also they provide mocks and practice interviews that will be beneficial for your selection process.
• Read English Newspaper and Novels - You improve your vocabularies and grammar,you should start reading English Newspaper as well as English Novels for better Vocabulary and Grammar.
• Practice Mathematics - You can check the previous year paper and first try to do those topics which comes for more marks.Most of the topics are related to 9th and 10th class Mathematics and some are from +2,so try to practice it as much as you can.This will help you to improve your speed in solving problems easily.And also please try to solve the question until you get the final result,because in Short Answer Questions,there will be no options,so you need to get the final answer to write in it.
• Solve Mocks - You can buy or get mock test from coaching classes or online classes,solving mocks will give you an idea of how to complete your paper at what time and what type of questions will come in Exam.So try to solve as much  mocks as you can.
• Be a time perfectionist - Always watch clock before solving a question,as it will help you to know that you are doing that question at your desired time or not and if you take more time to do that question,try to improve that.That can be your biggest weakness as many candidates who know every answer but still cannot able to crack the exam just because of time factor.

Hope This Helps

Best Of Luck!!!