Data Interpretation Section in CAT

The DI section in CAT is basically sub divided into two types of questions. First, the proper DI questions which have got charts/tables/graphs and questions are there based on these. Second, Analytical Reasoning (AR) caselets, where data is given in the form of some cluttered information and you are supposed to make a table or match them properly and answer the questions that follow. This article will focus on DI part; as in how to tackle it, what are the skills required to crack it and how to inculcate those skills.

There are two opinions about the DI section- one set of students feel  that it is the easiest section as there is hardly any theory involved whereas another set of students hate it as the amount of calculations involved are huge. Obviously the second set of students is not used to mental calculations or calculating using pencil and paper. Using calculators for last three years handicaps them. You would be surprised to know that a high school student can do calculations much faster and perform better than a graduate student in this section. This is because he in the habit of calculating using a pencil. Calculations do not draw an “OH NO” from them.

Speedier calculations are must

The basic ingredient of doing well is to master calculations. One should be thorough with Tables up to 20*20, Squares up to 30, cubes up to 20 and reciprocal percentage equivalents up to 30. The last part is an absolute must. By that I mean 1/1 is 100%, ½ is 50 %, 1/3 is 33.33 %, ¼ is 25%, 1/7 is 14.28% etc. You would be surprised how much time can be saved by simply memorizing these. Division will never bother you again. For e.g., if I want to find the percentage increase from 1300 to 1600; basically what I am looking at is 300/1300 *100 which is nothing but 3/13 as a reciprocal. Since I know 1/13 is 7.69% and therefore 3/13 should be 7.69*3, which is approximately 23.1%. I can actually get the answer in seconds without using even pencil!!

It also pays to remember various important fractions in percentages. For e.g., 37.5 percent is nothing but 3/8 and 62.5 percent is 5/8 th of a number. Another approach to calculate fast is breaking the percentage to simpler terms. For e.g., if I need to find 64.6% of 273, it would be so much better to find out 66.66% of 273 (basically 2/3) and subtract 2% from it. The final answer will be a little less than this. Therefore it will boil down to 182 – 2% (approximately 5.4, since 1% is 2.7) and, therefore, the answer is approximately 176.5.

The most important thing is not to know that you need to remember these tables; but it is to actually do them. Here, by experience, I will suggest that one should make a chart of all these tables/ squares etc and keep that chart at a place which is visible most of the time in a day. You will end up looking at it invariably while doing any non value added activities and thus automatically it will become a part of you. Never give a stipulated time for mugging these; that time never comes and you will be in a very famous first day of new month syndrome!!

Make calculations a part of your life

If you are a serious CAT aspirant; this is something you have to do. Wherever you are and whichever situation you are in, your focus should be on numbers and calculations.

If you are watching a cricket match, calculate asking run rate based on runs needed in overs left etc; calculate the economy rate of bowlers and try and understand the strike rate of bowlers etc. I am sure you will think that you might not be interested in cricket, its not about cricket, it is about the shift of focus to numbers and calculations. Even if you are very big fan of cricket and a serious CAT aspirant, how many of you actually know and try to find out Net Run Rate(NRR) which was so very crucial in determining the top 4 teams for semifinal clash in the recently concluded IPL. Had you tried, you would have realized it is so simple…its nothing but (Total runs scored/total over played)  - (total runs conceded/ total over bowled) in a match or tournament.

When you are at petrol pump and want to fill gas worth Rs. 100, please try to calculate mentally as to approximately how many liters of gas you will get, given the rate of petrol is Rs. 55 per litre. Don’t stop by thinking it should be less than 2 litres. All CAT aspirants are there only - what and where is the difference then? Do that extra effort as in how much less than 2 liters you will get. If you want to learn I can help you now. 2 litres you will get in Rs. 110 Rs. So, you give Rs. 10 less. So, the amount of petrol which you  will get lesser than 2 litres will be the amount of petrol that  you  can get in Rs. 10. Now in Rs. 10, you will get 10/55 litres, since in Rs. 55rs, you get 1litre. But 10/55 is nothing but 2/11 which is nothing but 18.18% (since 1/11 is 9.09%; reciprocal percentage won’t leave you.) So you will get approximately 0.18 liters less or you will get approx 1.82 liters in Rs 100. I know for starters it might sound a little tough…but If you want to see yourself in the IIMs, please do these practical things.

The idea is to eliminate our mindset that calculations are very tedious. More and more mental calculations will make you comfortable with playing around with numbers - a quality necessary for you to do well in DI.

Once you are through with the calculation syndrome, in my next article I will talk about how to answer the questions- as in what role does answer choices play in DI. I will then take AR as well. Wishing you all the best in preparations.

in this article I will talk about the role answer options play in DI and how to actually answer the questions.

The most important thing you must keep in mind is that you are there to mark the right answer. Please don’t get carried away or lose focus while doing the calculations. Don’t try to get the answer of the question to the nearest point of the decimal if the answer options are very far apart.
Eg. The four answer options are a)25%, b)40%, c)58% and d)70%. Here you don’t need to exactly calculate the answer. Even if you do an approximation you should be able to get the correct answer.

Sometimes, there is an option d) cannot be determined. In all such questions my sincere suggestion to each one of you is please read the question and the graph very carefully as in what data is given and what is being asked. My experience suggests that more than 90% of the time the answer is cannot be determined only. The graph will be of profit percentage contribution of various items and the question asked would be the percentage decline in sales of product A and I have found with plenty of good students that they invariably find the answer by calculating from the graph without realizing that the graph is of profits and the question asked is of sales. Please understand, the answer which you will calculate will always be there in the options and the sad part is once you get that and mark it, you will feel happy also!!!! I always keep telling in my class CAT is not a tough paper; its just tricky; it’s a test of playing with your sentiments!!! When you are out of the hall, you will realize there were at least 3-4 questions which were definitely in your reach which either you did wrong by some stupid silly mistake or you have simply not read them! So please take care of this small thing.

Sometimes, to make question little difficult, the answer options would be clubbed.
For eg; there is a graph followed by question: which of the following statements are true? I, II III.
Now the answer options are: a)only I; b) Only II ; c)Only III d) I and II e) II and III.
Now it might happen that you have to read all three statements but please don’t read for entertainment or otherwise. Read all only if you are unable to answer the question by reading few statements. Lets say, I read the first statement and I am sure its true. So please look at options carefully, now I am sure the option is either a or d in other words I now have to read only the II statement and completely avoid reading the III statement. If the II statement is also correct, I will mark the answer as d and if its wrong, I will mark the answer as a. These small small things will not only save your invaluable time but also fill you with tremendous confidence. Ultimately, you should be very focused that you just want to click the correct option.
Well, sometimes the options help us when we are in some doubts. Eg: the question is which of the following statements are true? a) b) c) d) all are true e) none are true. Now here, lets say I read the a) statement and I am sure its true. I will have to read the b) statement now as there is an option all. If I am sure that b is also true, I will surely mark d) as the answer without reading the c) statement; If I am sure its wrong; I will again mark the answer a) without reading the c) statement; but lets say I am not very sure of b, it’s an ambiguous statement, So here I have an opportunity to still get the question right by reading the statement c). If it is correct, the answer is d) and if it is wrong the answer is a).

The most tricky option is d) none of these. What you need to understand is none of these simply means the answer is not a, not b, not c. In other words, it can also mean cannot be determined (cbd). See, if the option cbd is there, we will become cautious and probably recheck the question but if the option is none of these, no such trigger will click in our mind and we might falter. So, for none of these you need to check the determinability of the question as well. Also, none of these can also mean “all the above” or both “a and b” and so on and therefore if the option d) none of these is there, and I read the a) option and find it correct, I should not mark it as the answer and rather read both b) and c) as well to be sure that only a) is the correct answer. The biggest dilemma which none of these gives is when the options a) b) c) are close and the answer we are getting is none of them but close to a).
Eg. a) 12 b) 14 c) 16 d) none of these. Here, after calculation if I am getting the answer as 20 or more, I will surely mark none of these but if I get the answer as 12.1 or something, I will be in real dilemma as to the answer should be 12 or none of these. Honestly friends, I have seen both cases in my teaching career so far and so this is a real problem with d) none of these option. Not to sound diplomatic though, I will go ahead and put my money on option a) 12 in that case. However, had the options were a) 12 b) 12.2 c) 12.4 d) none of these and here if I would have got 12.1 after calculations I will certainly mark the answer as d) none of these. Since the options are very close and the examiner wants me to be very accurate!

Well, that’s all I guess for answering DI…wish you all the very best and hope these basic things will help you score more and thus generate confidence. Shortly, in my next article I will talk about AR strategies especially game based questions as demanded by some of you.