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## Here’s how you should tackle reasoning and DI sections in the CAT

education Updated: May 22, 2012 18:41 IST
Hindustan Times

The reasoning and data interpretation (DI) areas of CAT are two of the most difficult and challenging areas in the test. However, successful test aspirants vouch for the fact that this is the most scoring of all areas and a good performance here will help them achieve the overall cut-off and brighten their chances of multiple IIM calls.

Data interpretation

DI has been an integral part of CAT since its inception. An analysis of CAT of recent years reveals that DI has had a significant weightage and the same trend is expected to continue into CAT 2011. Over the years, the questions that have appeared in this section can be classified under the following heads:
* Table
* Pie-chart
* Bar chart
* Stacked bar
* Reasoning based
* Games and tournaments
* 3D charts
* Network
* Maxima and minima

The skills required to crack questions in any of these formats are those of
A) Analysis and understanding of difficult/complicated data
B) Ability to do some serious number crunching

The skill mentioned in A (understand difficult/complicated data) is often more difficult to acquire and would require regular practice. One way to do this is to start with the study material books in DI and work out all the data interpretations sets. Once all these sets are solved, one would have a fair idea of the approach to be adopted to solve different ‘types’ of questions. Once the basic study material booklets are done, it is time to move onto the real simulation of CAT using some online practice tests. Students should ensure that they have paper and pen with them before attempting these online tests. In this way by working out the basic study material and the online tests, students would have prepared for the various Qs types that appear in CAT and also the way they appear in the online format.

Acquiring the skill mentioned in B (mastery over complex calculations) is often easier said than done. It is difficult to get over the old habits of scribbling numbers on a paper even for simple additions (what we did in school) and to trust our brain to add, subtract, multiply numbers without a piece of paper.

Once this mental practice is done, calculations will become easier and give you a high each time you do a more difficult calculation than what you thought you could.

As with many difficult things like riding a bicycle, riding a scooter etc speed math and number crunching requires constant practice — ask your parent or a sibling to give you difficult additions, multiplications and measure the time you take to arrive at the right answer. Over a period of time you will notice the time taken for these calculations reducing and the complexity of the Qs that you can handle going up significantly. One tool that helps in doing the complex calculations faster is using the approach of ‘fractions’ – the following illustration will make this clear.

Reasoning
Students who have ignored the reasoning area have often come to grief in previous editions of CAT given the high proportion of such Qs appearing in CAT in the last five years. The questions in logic can be broadly said to come from three areas viz puzzles, venn diagrams and cubes, deductions and logical connectives.

Of these, the questions on puzzles have been most common followed by deductions and Venn diagrams. Puzzle books like the ones by Shakuntala Devi, George Summers etc. often provide exposure to high level logic puzzles and the approaches to tackle them.

The area that requires most effort and often proves tricky is the one on cubes as the student needs to visualise the third dimension of the cube in his mind and then solve the given questions. Questions on the reasoning and data interpretation areas of CAT are often perceived to be difficult and tricky, however with sufficient practice you can convert this into an opportunity to score marks

Example 1
Suppose one is asked to find out 14.3% of 771400 – the usual way is to multiply 771400 by 14.3 and dividing the resultant by 100. However if one is aware of fractions then 14.3% - 1/7 of 100 which means that we just need 1/7th of 771400 (a convenient division as the given number is a multiple of 7!).

Students often learn the fractions by rote and can easily reel off 1/4, 1/5, 1/6, 1/7 …. and so on. However it is not enough if one knows the percentage equivalent of 1/7. What is required are the multiples of 1/7 i.e., 2/7, 3/7, 4/7 … and so on. The following illustration will clarify this

Example 2
Suppose one is asked to find out 42.91% of 56280 – the fastest way of doing this is to realize that 42.91% is very close to 3/7 as a fraction and one needs to find 3/7 of 56280 (a number which is divisible by 7). Once you grasp the nuances of such calculations, this aspect of DI becomes a breeze

Sai Kumar is an alumnus of IIM Bangalore and is the director of TIME Mumbai

First Published: May 22, 2012 18:35 IST