Elimination Tips and Tricks to solve IIT JEE Problems

Solving 90 questions in 180 minutes is not an easy task. And the fact that most of the questions belong to the medium and hard level does not help either. There are quite a few tricks that I used during my JEE Mains and I think you can find them helpful.

1. The Sherlock Theory - This is what I prefer to call it for it is based on a famous Sherlock quote, “When you eliminate the impossible, whatever remains, however improbable, must be true.” Read the question and carefully go through all the options and try to eliminate those options which you definitely know are wrong. You can get better at this with practice . This trick works very well with Physics and Chemistry questions.
2. Dimensional Analysis - This is one of the first topics we learn in 11th and usually neglect it because no direct question is asked from it. But what we should know is, this topic can be helpful in solving questions from other topics. Whenever you are asked to find an expression for some physical quantity in terms of other quantities, do a quick dimensional analysis. Eliminate the wrong ones and you will be left with either the right answer or answers with variations in number constants. The problem becomes much easier now since all you have to worry about is numbers. This trick is most helpful for Physics section and sometimes in Chemistry as well.
3. Calculus - How can we leave Maths behind then? Many times we are asked to solve a integral which requires more than two pages, a lot of formulae and hence, a lot of time to solve. Instead, use the basics of calculus. Instead of integrating the expression, differentiate the options one by one. Here comes the dilemma - which option to choose first? Go for The Sherlock Theory. Even if you don’t get the answer in the first attempt, you get a fair idea of what the answer can be and you can choose the next option accordingly. This trick also works if you don’t have any idea how to approach the integration.
4. Rounding off - This trick is a little risky and is not applicable to all the questions. Be careful while using it. When you have to solve a numerical problem and the terms involved are very bizzare or in decimal froms, just round them off to the nearest integer and expect the actual answer to be that much away from the answer you get. Again, this trick works well if and only if the options are not very close to each other and you are good in handling numbers. For example, you can round off 208 to 210 (or even 200 if the options permit) or 11.2 to 11.
5. Logarithmic Table - We usually use the logarithmic table for solving numericals which are difficult to solve by basic maths. What if you could use the logarithmic table in JEE Mains as well? Yes, I know that the table is not allowed in the examination hall. How about you memorize the logarithmic values for all the integers (1 to 9)? Or, if you get good at it, you can even learn the values for 1.5, 2.5, …,9.5. Instead of doing calculations of huge numbers, use trick 4 and then their logarithmic values to simplify the calculation. And, instead of going for anti-logarithms, you can just try to remember that integer whose logarithm is closest to the value you got. This trick, too, is very difficult and should be used only if you are confident enough and have practiced it enough times. Also, do not try to learn this trick in the last one month or so. You may end up disturbing your other methods.

Hope you find this helpful and solve a few more questions than you normally would.