The Art Of Guessing

"Seriously? Is guessing really an art and can it be mastered by practice?"
Yes it can. And this exactly would be our topic of discussion in this post.
I would like to make it clear that it is not like the top-rankers solve all the questions properly. Rather they are smart enough to outwit the examiner. Think of it as a game. You get equal points even if you blindly start solving the question or you apply some trick by eliminating the options. So what is wrong in doing the latter ?
With the growing numbers of negative marking and advent of multi-correct questions in JEE pattern, guessing has been increasingly risky but if applied in the right manner it is fruitful. Only that you have to be cautious before applying it.

Situations where you can guess:-

• Dimensional Analysis can be of your help to guess. While it is use in physics is obvious where you can eliminate the options if they don't follow the dimensions of what is asked in the questions(which is rare btw :P) what I would like to focus on is its use in Maths. Suppose there is some condition given in terms of some variables which will also be fulfilled if you multiply each variable by 2 and in the question you have been asked the sum of these variables. Then you can definitely say that under the transformation x->2x the sum must not change hence it must be zero. 
• In those questions addressed to a general case you can solve them by taking a specific case iff it meets all the conditions given in the problem. Then you can be sure that the answer you get by solving this special case would be the same as the answer you ought to get after solving for the general case. E.g Square as a special case of parallelogram
• The Obvious One- When you can eliminate the options. But be careful here you must calculate the probability of your answer being correct depending on how many options you have eliminated. Get some probability into action and ensure that you get a net benefit despite negative marking in that question.

These are just some examples. Of course there are many more which I remembered in my JEE days but fail to recollect now. Of course there are many which I did not even think of but you can discover for your own good. So next time you are unable to solve a question think once to find guessing methods which can be applied to solve this problem. Note that it would only be 1 in 30 questions that you would be able to guess the answer because the problem-setters are also becoming increasingly smart but who knows that might turn out to give you an edge over the others. In exam if a guessing method naturally comes to your mind(which will after practice) then only you should go for it else don't waste much time on thinking about the methods to guess and move on to the next problem. This post is just to remind you to open your mind to accept all types of solutions and give equal respect to each. However useful this approach might be to score well in the exams, while learning you must also solve the questions properly because within that solution only will lie the beauty of the problem.

-Heisenberg