DI-LR Strat
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How to crack the DI-LR section of the CAT – I

Just like I keep getting queries on how to increase RC accuracy, despite the Last Mile To CAT sessions, I keep getting queries around the DI-LR section as well.

Given the great response that the RC posts got, I thought I’ll dive really deep down into the DI-LR sets of CAT 2017 and see if I can come up with some kernel of truth beyond just the solving of the set that can help aspirants approach the solving of the sets better.

I am not going to take up the selection of the sets in these set of posts — I have already done that in these previous posts, here and here. So if you do not know the process to select you should first look at these posts.

I am going to solely focus on

  • solving these sets cleanly
  • bringing out the reason why these sets seem tougher than usual
  • highlighting the skills or the logical reasoning chops you need to strengthen and
  • the ways to do the same

The Pizza Set

Funky Pizzaria was required to supply pizzas to three different parties. The total number of pizzas it had to deliver was 800, 70% of which were to be delivered to Party 3 and the rest equally divided between Party 1 and Party 2.

Pizzas could be of Thin Crust (T) or Deep Dish (D) variety and come in either Normal Cheese (NC) or Extra Cheese (EC) versions. Hence, there are four types of pizzas: T-NC, T-EC, D-NC, and D-EC. Partial information about proportions of T and NC pizzas ordered by the three parties is given below:

Thin Crust (T) Normal Cheese (NC)
Party 1 .6
Party 2 .55 .3
Party 3 .65
Total .375 .52

1. How many Thin Crust pizzas were to be delivered to Party 3?

  1. 398
  2. 162
  3. 196
  4. 364

2. How many Normal Cheese pizzas were required to be delivered to Party 1?

  1. 104
  2. 84
  3. 16
  4. 196

3. For Party 2 if 50% of the Normal Cheese pizzas were of Thin Crust variety, what was the difference between the numbers of T-EC and D-EC pizzas to be delivered to Party 2?

  1. 18
  2. 12
  3. 30
  4. 24

4. Suppose that a T-NC pizza cost as much as a D-NC pizza, but 3/5th of the price of a D-EC pizza. A D-EC pizza costs Rs. 50 more than a T-EC pizza and the latter costs Rs. 500. If 25% of the Normal Cheese pizzas delivered to Party 1 were of Deep Dish variety, what was the total bill for Party 1?

  1. Rs. 59480
  2. Rs. 59840
  3. Rs. 42520
  4. Rs. 45240

How to process the information

As I read the set I can see that they have given how many pizzas were delivered to each of the three parties — so I know the totals of the rows.

I can also calculate the totals of the columns — the number of TC and number of NC.

Only two cells are missing and at this point and they can be calculated in a trice. It is important to look at the questions at this point — once the understanding of the set is done.

The first two questions are asking for the two missing values.

Also, the moment I look at the values — .375 and 800 — I know that the calculation is easy. If you do not see this then before you ask anyone else how to improve your DI-LR scores, you need to fix this — your number crunching skills.

So you know that you can pocket 6 marks in about 6 minutes easily. So I would rate this set an 8 out of 10.

To take you through the process of solving this set, I decided to record a video of the solving so that you can see how to use the paper effectively to solve cleanly and also get a fair idea of how the numbers should be broken down during calculation.


The Electives Confusion

There were seven elective courses – El to E7 – running in a specific term in a college. Each of the 300 students enrolled had chosen just one elective from among these seven. However, before the start of the term, E7 was withdrawn as the instructor concerned had left the college. The students who had opted for E7 were allowed to join any of the remaining electives. Also, the students who had chosen other electives were given one chance to change their choice. The table below captures the movement of the students from one elective to another during this process. Movement from one elective to the same elective simply means no movement. Some numbers in the table got accidentally erased; however, it is known that these were either 0 or 1.

CAT 2017 Slot 2 - Set 1 - 1

Further, the following are known:

  1. Before the change process there were 6 more students in E1 than in E4, but after the reshuffle, the number of students in E4 was 3 more than that in E1.
  2. The number of students in E2 increased by 30 after the change process.
  3. Before the change process, E4 had 2 more students than E6, while E2 had 10 more students than E3.

5. How many elective courses among E1 to E6 had a decrease in their enrollments after the change process?

  1. 4
  2. 1
  3. 2
  4. 3

6. After the change process, which of the following is the correct sequence of the number of students in the six electives E1 to E6?

  1. 19, 76, 79, 21, 45, 60
  2. 19, 76, 78, 22, 45, 60
  3. 18, 76, 79, 23, 43, 61
  4. 18, 76, 79, 21, 45, 61

7. After the change process, which course among E1 to E6 had the largest change in its enrollment as a percentage of its original enrollment?

  1. E1
  2. E2
  3. E3
  4. E6

8. Later, the college imposed a condition that if after the change of electives, the enrollment in any elective (other than E7) dropped to less than 20 students, all the students who had left that course will be required to re-enroll for that elective. Which of the following is a correct sequence of electives in decreasing order of their final enrollments?

  1. E2, E3, E6, E5, E1, E4
  2. E3, E2, E6, E5, E4, E1
  3. E2, E5, E3, E1, E4, E6
  4. E2, E3, E5, E6, E1, E3

Definitely a heavier set

This set is definitely tougher to understand than the previous one. As far as the table goes

  • there are a lot of missing values and
  • the values have to be reasoned out and not calculated like the previous set

If you look at the questions as well, you can see that there is a scope of making silly mistakes and if one has to tread carefully, one will end up taking a lot of time.

I will rate this a 6 out of 10.

It will be a set I will come back to only if I have no other sets rated above 7.


 The Old Woman and her Wealth

An old woman had the following assets:

(a) Rs. 70 lakh in bank deposits

(b) 1 house worth Rs. 50 lakh

(c) 3 flats, each worth Rs. 30 lakh

(d) Certain number of gold coins, each worth Rs. 1 lakh

She wanted to distribute her assets among her three children; Neeta, Seeta, and Geeta. The house, any of the flats or any of the coins were not to be split. That is, the house went entirely to one child; a flat went to one child and similarly, a gold coin went to one child.

9. Among the three, Neeta received the least amount in bank deposits, while Geeta received the highest. The value of the assets was distributed equally among the children, as were the gold coins. How much did Seeta receive in bank deposits (in lakhs of rupees)?

  1. 30
  2. 40
  3. 20
  4. 10

10. Among the three, Neeta received the least amount in bank deposits, while Geeta received the highest. The value of the assets was distributed equally among the children, as were the gold coins. How many flats did Neeta receive?

Enter your response (as an integer) using the virtual keyboard.

11. The value of the assets distributed among Neeta, Seeta and Geeta was in the ratio of 1:2:3, while the gold coins were distributed among them in the ratio of 2:3:4. One child got all three flats and she did not get the house. One child, other than Geeta, got Rs. 30 lakh in bank deposits. How many gold coins did the old woman have?

  1. 72
  2. 90
  3. 180
  4. 216

12. The value of the assets distributed among Neeta, Seeta and Geeta was in the ratio of 1:2:3, while the gold coins were distributed among them in the ratio of 2:3:4. One child got all three flats and she did not get the house. One child, other than Geeta, got Rs. 30 lakh in bank deposits. How much did Geeta get in bank deposits (in lakhs of rupees)?

Enter your response (as an integer) using the virtual keyboard.

Seems easy but unfamiliar

This set seems easy at first glance since the data is fairly straightforward. This is for those who have read the previous posts on DI-LR a classic example of Non-Standard-Plugin-Open Set.

If you take a look at the questions you will find that 1 & 2 have the same data and ask for different information. This means that if you solve 1, you get the answer to 2 as well and the same applies to 3 & 4.

The information for 1 and 2 is simple, all wealth and all coins are divided equally, so the situation is simple enough to execute. But the information for 3 and 4 is complex and you wouldn’t want to get into it.

So I would rate this 7 out of 10, do only the first two questions to get 6 marks in about 4 minutes and exit the set. This is how I would go about doing it.


The Dormitory Set

At a management school, the oldest 10 dorms, numbered 1 to 10, need to be repaired urgently, The following diagram represents the estimated repair costs (in Rs. Crores) for the 10 dorms. For any dorm, the estimated repair cost (in Rs. Crores) is an integer. Repairs with estimated cost Rs. 1 or 2 Crores are considered light repairs, repairs with an estimated cost Rs. 3 or 4 are considered moderate repairs and repairs with an estimated cost Rs. 5 or 6 Crores are considered extensive repairs.

CAT 2017 Slot 2 - Dormitory

Further, the following are known:

  1. 1. Odd-numbered dorms do not need light repair; even-numbered dorms do not need moderate repair and dorms, whose numbers are divisible by 3, do not need extensive repair.
  2. 2. Dorms 4 to 9 all need different repair costs, with Dorm 7 needing the maximum and Dorm 8 needing the minimum

13. Which of the following is NOT necessarily true?

  1. Dorm 1 needs a moderate repair
  2. Dorm 5 repair will cost no more than Rs. 4 Crores
  3. Dorm 7 needs an extensive repair
  4. Dorm 10 repair will cost no more than Rs. 4 Crores

14. What is the total cost of repairing the odd-numbered dorms (in Rs. Crores)?

Enter your response (as an integer) using the virtual keyboard.

Further information for questions 15 and 16:

  1. 4 of the 10 dorms needing repair are women’s dorms and need a total of Rs. 20 Crores for repair.
  2. Only one of Dorms 1 to 5 is a women’s dorm.

15. What is the cost for repairing Dorm 9 (in Rs. Crores)?

Enter your response (as an integer) using the virtual keyboard.

16. Which of the following is a women’s dorm?

  1. Dorm
  2. Dorm
  3. Dorm
  4. Dorm 10

In terms of information, this set does not have too many complications. The tricky part is that unlike the first set where the representation was a simple table. This set cannot be represented as simplistically. You need to find out the best way to represent the data.

From the wording of the first question — which of the following is not necessarily true — you will realize that you will not be able to fix all the rooms and all the costs. Some rooms will remain unallocated since the phrase is not necessarily and hence may be true.

I will rate this set 7 out of 10.

The first trick is to represent this properly. I don’t think what I have come up with is the best method but this worked for me.


A Cup of Tea

A tea taster was assigned to rate teas from six different locations – Munnar, Wayanad, Ooty, Darjeeling, Assam, and Himachal. These teas were placed in six cups, numbered 1 to 6, not necessarily in the same order. The tea taster was asked to rate these teas on the strength of their flavor on a scale of 1 to 10. He gave a unique integer rating to each tea. Some other information is given below:

  1. Cup 6 contained tea from Himachal.
  2. Tea from Ooty got the highest rating, but it was not in Cup 3.
  3. The rating of tea in Cup 3 was double the rating of the tea in Cup 5.
  4. Only two cups got ratings in even numbers.
  5. Cup 2 got the minimum rating and this rating was an even number.
  6. Tea in Cup 3 got a higher rating than that in Cup 1.
  7. The rating of tea from Wayanad was more than the rating of tea from Munnar but less than that from Assam.

17. What was the second highest rating given?

Enter your response (as an integer) using the virtual keyboard.

18. What was the number of the cup that contained tea from Ooty?

Enter your response (as an integer) using the virtual keyboard.

19. If the tea from Munnar did not get the minimum rating, what was the rating of the tea from Wayanad?

  1. 3
  2. 5
  3. 1
  4. 6

20. If cups containing teas from Wayanad and Ooty had consecutive numbers, which of the following statements may be true?

  1. Cup 5 contains tea from Assam
  2. Cup 1 contains tea from Darjeeling
  3. Tea from Wayanad got a rating of 6
  4. Darjeeling Tea got the minimum rating

 

This is the first set that seems to follow the typical format of a Logical Reasoning Set. Three variables and not a lot of conditions. But is it that simple?

There is more to this set than meets the eye if you read the conditions properly.

While the set is straightforward,  6 out of 7 conditions are deductive and only one is a plugin condition (please read the previous two posts on DI-LR to know what I mean by a plugin and a deductive condition)

So, you should be a bit wary about this set and not jump into it before the Pizza Set.

I would rate it a 7.5 out of 10.

Let us look at how you should have gone about solving this set in the least possible amount of time.


The Queen Of Chess

In an 8 × 8 chessboard a queen placed anywhere can attack another piece if the piece is present in the same row, or in the same column or in any diagonal position in any possible 4 directions, provided there is no other piece in between in the path from the queen to that piece.

The columns are labeled a to h (left to right) and the rows are numbered 1 to 8 (bottom to top). The position of a piece is given by the combination of column and row labels. For example, position c5 means that the piece is in the cth column and 5th row.

21. If the queen is at c5, and the other pieces at positions c2, g1, g3, g5 and a3, how many are under attack by the queen? There are no other pieces on the board.

  1. 2
  2. 3
  3. 4
  4. 5

22. If the other pieces are only at positions a1, a3, b4, d7, h7, and h8, then which of the following positions of the queen results in the maximum number of pieces being under attack?

  1. f8
  2. a7
  3. c1
  4. d3

23. If the other pieces are only at positions a1, a3, b4, d7, h7, and h8, then from how many positions the queen cannot attack any of the pieces?

  1. 0
  2. 3
  3. 4
  4. 6

24. Suppose the queen is the only piece on the board and it is at position d5. In how many positions can another piece be placed on the board such that it is safe from attack from the queen?

  1. 32
  2. 35
  3. 36
  4. 37

This is the easiest set of the lot. Those who know chess will not even have to read the description you will go straightaway to the set.

I would rate this an 8 out of 10since there is no ambiguity whatsoever and all one needs to do is put one’s head down and draw properly to collect 12 marks in 12 minutes.


Choosing the right set is key

From this and from my previous posts you would have seen that choosing the right set is key.

An unwisely chosen set can mean getting stuck for 20 minutes and wasting another 18 months of your life at another CAT attempt.

So while you might think you are following the steps outlined in the previous posts, you might still be doing it superficially since you want to save time and get to the solving.

But the key is to look deeper when you look. It boils down to operating at higher levels of concentration. It is the difference between spending 30 seconds and viewing the surface of the question and spending 45 seconds and seeing through to the bottom of it.

A simple example would be how one evaluates the A Cup of Tea set.

In the next post, I will solve the two sets that are left and answer the big questions —

  • What is making these CAT DI-LR sets unique or different from traditional sets
  • What is the unique skill that these DI-LR sets are testing?
  • Do they test a specific kind of reasoning that makes most students uncomfortable?
  • How do you develop this kind of reasoning?

Keep prepping.

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15 Comments

  1. sir, i solved every set on my own, but my score in simcats is still in the range of 25-30, I usually select the right set but still get stuck after a point. What should i do?

    Like

    • The reason you are getting stuck can be because of two reasons which you can determine by answering the following questions:

      1. Did you represent the sets the same way I did or in other words was your method of transferring the data onto the rough sheet the most optimal.

      2. Do you constantly ensure that you are going back to conditions and running through them and using the unused conidition.

      Most of the time the core reason for getting stuck is that being unable to use all conditions. Test-takers are left with one or two conditions that they do not manage to use in conjunction with other conditions.

      So after a point, they stop looking at the conditions and try to fix the pattern or the arrangement in their by trial and error rather than letting the conditions show the way.

      I think this will be the main reason why you are getting stuck.

      Evaluate your solving process and make that better before you start solving more sets. I will write more about this in the second DI-LR post.

      Hope this clarifies,

      All the best!

      Like

  2. Pingback: How to crack the DI-LR section of the CAT – 2 – The CAT Writer

  3. Harsh Pratap Singh says

    Sir, sometime the trick to solve the set is to rearrange the table. I want to know how to do that like you did in these examples because sometimes it doesn’t click.

    Like

  4. Harsh Pratap Singh says

    the pizza and the cup of tea set. and one more thing when you were in hyd you gave ur email id for any tips, doubts or methods i.e tony@imsindia.com, in this is it tony or Tony.

    Like

    • Well in both cases one starts from what we have and we need to determine. The way one should always visualize the table or any other form of representation is that you can fill in the things you need to determine into the table/figure. So always represent in such a way that the given information is fixed and you create the right space to fill in the required information.

      In the Pizza Set, the required information is numbers of pizzas so it makes a sense to draw a table with blank spaces for filling in values.

      In the Tea-Set, what is fixed are the numbers and what is variable are the ratings and the places. The key is to view the given information not a table or a chart but as information and to view the representation, not as a 2*2 or a3*3 table but as, a thing that you have to invent or arrive at depending on the information. I thought I did the best thing with the Dormitory set 🙂

      I’ll maybe do a post dedicated to the various steps into solving a DI-LR set and elaborate on the representation bit.

      You can write to me at tony@imsindia.com

      Like

  5. Pingback: How tough was the DI-LR on CAT 2017 Slot 1 ? | The CAT Writer

    • It’s not a solution to the paper but an analysis. I would have left it in the paper as well. You can take the paper as a test on MYIMS and get the solution or find it elsewhere online 🙂

      Like

  6. Mayank says

    In the pizza set I am unable to understand how the value of 364 came in under NC. Can you please explain?

    Like

    • Hi Mayank,

      I changed the table from an image to an actual table after I first made this post.

      I incorrectly put .65 under TC instead of NC for Party 3 — .65 of 560 gives 364.

      Thanks for raising the query.

      All the best!

      Like

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