CAT Wise

CAT wise

DATA INTERPRETATION AND LOGICAL REASONING REMAINS ONE OF THE LEAST PREPARED FOR SECTIONS. HOW TO MAKE THE MOST OF THIS SECTION,WHICH CARRIES ONE-THIRD WEIGHTAGE OF THE CAT

IN the last article we had discussed the lines of preparations that you need to follow when you are preparing for the Verbal Ability and the Quantitative Aptitude section. In today's article we would like to focus on the all important section of Data Interpretation & Logical Reasoning.
   One thing you need to realise is that even though this section has always had one-third the weightage of the CAT paper, yet it remains one of the least prepared for sections. Perhaps, the major reason for the same is that unlike the other sections- it is practically impossible to define portion in this section.
   Thus, while there is a definite portion that can be defined for Quants, and at least some contours of a portion definition for English preparation, students and trainers are at a loss when it comes to defining what to study for in this section.
   Perhaps, part of the solution to this problem is to come out of your conventional preparation mode - the way everyone prepares for university examinations- define portion, study theory, practise questions, revise theory.
   Instead, what you would need to focus on is to develop an ability to understand what the basic unit of learning is, when it comes to DI. I would tend to advocate to you the skills set approach to developing your DI & LR skills.
   Looking at it from another point of view- as we had said last week- preparations for the DI & LR section need to be organised under four basic umbrellas-

1) Traditional Data Interpretation-

This is the conventional DI question based on charts and graphs. Skill sets required to do well in this question type include the following:
   a) Your knowledge of some basic areas of quantitative aptitude. Chapters which you need to be thorough with are Ratio & Proportions, Percentages, Progression, Basic concepts of numbers, averages, alligations.
   b) The ability to understand data and identify variables and their relationships.
   c) Calculation skills- you would be well advised to hone your ability to add two digit numbers, calculate and compare ratios and also develop your ability to approximate calculations involving big numbers.
   
2) Advanced Reasoning Based Data Interpretations:

(first made its appearance in 2003 CAT and can be typically defined as questions that have some data based information running behind them while at the same time one would need to make certain logical deductions. Unlike, traditional data Interpretation questions, in these questions data is normally presented in a disguised format. So obviously the skill you need to develop for doing well in this question type is to develop your ability to interpret data and discover hidden linkages between the various variables presented.
   One sees a lot of aspirants being shaken by these question types and one knows for a fact that more than 80 percent of the people preparing for CAT are scared of this question type.
   To illustrate what I mean, let us take a simple situation.

THE ANATOMY OF AN ADVANCED REASONING BASED DI QUESTION:

Suppose there is a narrator of a story who tells you that there is a situation wherein there is a bus going from Delhi to Bombay and it has two stops in between say at Ahmedabad and Pune. Next, he tells you the following statements:
   a) When the bus left Delhi,there were 80 passengers.
   b) When the bus left Ahmedabad, there were 83 passengers.
   c) When the bus arrived at Bombay there were 75 passengers in the bus.
   What sense can you make out of this information? Suppose someone makes a conclusion that in Ahmedabad there must have been three new passengers who got into the bus. Would that thinking be correct?
   Obviously, most of you would be shouting out loud in your minds as you read this- that we cannot conclude that there were three new passengers who got into the bus.
   The difference between the number of passengers who left Delhi and the number of passengers who left Ahmedabad must obviously be a function of two distinct variables-
   i) The number of people who got down from the bus,
   ii) The number of people who got into the bus.
   Thus, obviously the only thing you can conclude here is that in Ahmedabad, there were three extra people who got in (when compared to the number of passengers who got down from the bus).
   Why are we using this article to tell you the obvious? Why are we wasting your time telling you this:
   Well consider one of the toughest questions that have happened in the CAT DI sections ever:
   The year is 2089. Beijing, London, New York, and Paris are in contention to host the 2096 Olympics. The eventual winner is determined through several rounds of voting by members of the IOC with each member representing a different city. All the four cities in contention are also represented in IOC.
   
• In any round of voting, the city receiving the lowest number of votes in that round gets eliminated. The survivor after the last round of voting gets to host the event.
   
• A member is allowed to cast votes for at most two different cities in all rounds of voting combined. Hence, a member becomes ineligible to cast a cost in a given round if both the cities (s)he voted for in earlier rounds are out of contention in that round of voting. (Note: Your interpretation of this sentence should be that, this is one way of becoming ineligible to vote- if you voted for a particular city in the first round and that city got eliminated, and if you voted for another city in the second round and that city too got eliminated in that round, then you cannot vote in the third round. Passenger getting out of the bus anyone?)
   
• A member is also ineligible to cost vote in a round if the city (s)he represents is in contention in that round of voting. (Note: Do you realise that this is giving us a way of making a member who is ineligible to vote eligible? Also do you see that after every round starting after the first round itself, exactly one member will become eligible to vote. Do you see passengers getting into the bus? One passenger at a time?)
   
• As long as the member is eligible,(s)he must vote and vote for only one candidate city in any round of voting.
   Now with this information if you are given the information that 83 people voted in the second round and there is missing information about the number of people who voted in the first round- can't you realise that 82 people must have voted in the first round? (Obviously, because from the first round to the second round only one new person would be eligible to vote. The rule for making people ineligible to vote is only going to come into the picture in the third round for the first time- so the difference between the number of people who voted in the first round must be one less than the number who voted in the second roun).
Further if you are told that, in the third round 75 people voted. Can you see that 1 person must have entered and 9 people must have dropped out? And those nine people must have voted for the city eliminated in the first round and the also voted for the city eliminated for in the second round.
(Isn't it the same logic as: Bus leaves from Delhi with an unknown number of passengers, reaches Ahmedabad and when it leaves Ahmedabad there are 83 passengers. It is also known that no one is allowed to get down in Ahmedabad and exactly 1 person entered in Ahmedabad. Further, one person more enters in Pune and when the bus leaves Pune there are 75 passengers in the bus. So, obviously nine people must have got down in Pune).
What surprises, is the fact that this question is amongst the toughest questions to have appeared in CAT. And if people cannot correlate the logic of what they see in their daily lives to what is asked in CAT DI- the CAT can continue to merrily remain a mystery for lakhs of aspirants every year.
The other two lines of preparation in this section are:
3) CAT Type Reasoning
4) Non CAT Reasoning
We would talk about these and many more crucial issues in our next article of this series.