Friday, March 9th, 2018
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family. The following table will give you some idea of terminology of relationships.
|Father of grandfather or grandmother||Great grandfather||Daughter of father or mother||Sister|
|Mother of grandfather or grandmother||Great grandmother||Son of second wife of father||Step brother|
|Father of father or mother||Grandfather||Daughter of second wife of father||Step sister|
|Mother of father or mother||Grandmother||Son/daughter of uncle/aunt||Cousin|
|Wife of grandfather||Grandmother||Brother of husband or wife||Brother-in-law|
|Husband of grandmother||Grandfather||Sister of husband or wife||Sister-in-law|
|Father-in-law of father/mother||Grandfather||Husband of sister/sister-in-law||Brother-in-law|
|Mother-in-law of father/mother||Grandmother||Son of father||Oneself/Brother|
|Father’s father/mother only||Father||Mother of son/daughter||Oneself/Wife|
|Only daughter-in-law of father’s father/father’s mother||Mother||Father of daughter/son||Oneself/husband|
|Husband of mother||Father||Son of son of grandmother/grandfather||Brother/Oneself
|Wife of father||Mother||Daughter of son of grandmother/grandfather||Cousin/Oneself
|Second wife of father||Step mother||Son of brother or sister||Nephew|
|Brother of father||Uncle||Daughter of brother/sister||Niece|
|Brother of mother||Maternal Uncle||Grandson of father/mother||Son/Nephew|
|Sister of father||Aunt||Granddaughter of father/mother||Daughter or Niece|
|Sister of mother||Maternal Aunt||Husband of daughter||Son-in-law|
|Husband of aunt||Uncle||Wife of brother/brother-in-law||Sister-in-law|
|Wife of uncle||Aunt||Wife of son||Daughter-in-law|
|Son of grandfather/grandmother||Father/Uncle||Son of son/Daughter||Grandson|
|Daughter of father-in-law/mother-in-law of father||Mother/Aunt||Daughter of son/Daughter||Granddaughter|
|Father of wife/husband||Father-in-law||Son’s/Daughter’s grandson||Great Grandson|
|Mother of wife/husband||Mother-in-law||Son’s/Daughter’s granddaughter||Great granddaughter|
|Children of same parents||Siblings|
|Father’s/Mother’s only son/daughter||Oneself|
|Son of father or mother||Brother|
The questions on blood relations are of following three types
Since I have already discussed coded relationships, in this blog, I’ll explain techniques and methods to solve the other two kinds.
Let’s start with the first one
BASED ON STATEMENTS/ CONVERSATIONS
The questions in this category are generally a dialogue/ conversation between two people and followed up with a question on the basis of information provided in the conversation. Given below are some examples of this kind along with the method to solve them.
Ram said to Hari.” The boy playing with football is the younger of the two brothers of the daughter of my father’s wife”. Then how the boy playing football is related to Ram?
Pointing to a man in the photograph a woman said, “His brother’s father is the only son of my grandfather”. How is the woman related to the man in the photograph?
The approach you need to follow to solve these questions is Backtracking.
Backtracking means beginning with last information and proceed backward. For example, if it’s given that he is the son of the mother of my grandfather’s daughter, then we start with the last information provided: ‘Grandfather’s daughter’. Now, Grandfather’s daughter means Aunt (sister of the father). Now, mother of my grandfather’s daughter becomes ‘mother of my aunt’ hence grandmother. Therefore, son of my grandmother become either my father or uncle.
Now let’s try this technique in the example given above.
Example 1: “The boy playing with football is the younger of the two brothers of the daughter of my father’s wife.” Here the last piece of information is
Example 2: “His brother’s father is the only son of my grandfather.”
Now we can move on to the second kind of problems
BASED ON PUZZLES
In this type, usually set of information is given followed up with series of questions. And with the help of this info. you need to answer those questions. The technique to solve them is family tree diagrams.
You can draw tree diagrams in the following fashion.
As we have now understood the method to draw the diagram let’s move forth and practice some questions.
Example1: In a family, there are six members- A, B, C, D, E and F. A and B are a married couple, A being a male member. D is the only son of C, who is the brother of A. E is the sister of D. B is the daughter-in-law of F, whose husband has died.
How F has related to A?
How is E related to C?
Who is C to B?
How many male members are there in the family?
To solve such questions
Now let’s solve the problem given above
Sol 1: The first sentence is USI while all other are is actual information. Since, as suggested above we should begin with the parent-child relationship. And the third sentence depicts parent-child relationship i.e. D is the only son of C who’s a brother of A. Therefore, the diagram is as follows
Now we should look info. that tells more about A, D or C. The second sentence tells us more about A. So, we’ll incorporate that into the diagram.
Now we shall add the leftover information and the one that fits the most in the current diagram is the relationship between D and E.
We have finally reached in the position of completing our tree diagram by incorporating the final information which is about F who is a female since her husband had died. And B is her daughter-in-law. Therefore, she’s the mother of A and C.
Since we are done with the family tree we can easily answer all the above question on the basis of this diagram.
Let’s do another example of such kind of questions but let’s add another dimension to it i.e. the problems based on Blood relations and professions. This kind of questions can be asked in the exam. Given below is an example of the problem following the method to solve it.
What is the profession of T?
How’s P related to T?
How many male members are there in the family?
What is the profession of P?
To solve such problems in the exam you need to proceed exactly like the way you did in the earlier example except now you have to take profession also into account. To do this you just need to add their profession below their name in the family tree diagram. Let’s solve this now.
As you can notice the (i) and (vi) sentence are U.S.I. And the fifth sentence denotes parent-child relation. So, we’ll start our tree diagram using the information that Q is the mother of T and U. And as the sentence doesn’t tell us anything about their profession we will leave the place blank.
Now as we did earlier we’ll now look for some info. that involves something more about Q, T, and U. It tells us that U is a psychologist and the other info is that doctor is a grandfather of U. Now as Q is U’s mother. This implies Q is the daughter-in-law of the doctor.
Examine that there’s no direct piece of information left that connects any dot with our current family tree. So, we’ll draw separate tree diagrams for them. The information is that S is married to P and R, the jeweler is married to a lawyer. Hence,
Note that It’s given there are only two married couples in the family. Therefore, the doctor’s wife must be alive. Hence S, the manager must be doctor’s wife. And R, the jeweler is married to the lawyer who will be Q. Now we have exhausted and incorporated all info. and nothing could be said about the sex of T and U. But with the first line tells us about the profession of T i.e. is an engineer. Thus, the family tree looks like:
Again, with help of the above tree diagram, we can quickly answer all the questions followed the problem above.
This is just one example of how more dimensions can be added to Blood relation problems. These can also be merged with other reasoning concepts like seating arrangement and directions etc. This makes them more time-consuming. But in an exam, you need to be quick irrespective of the various combinations and dimensions in these problems and the speed can only be developed if you practice many varieties of such problems.
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All questions from CAT 2017 Logical Reasoning
Logical Reasoning – Set 1: A high security research lab requires the researchers to set a pass key sequence based on the scan of the five fingers of their left hands.
Logical Reasoning – Set 2: Eight friends: Ajit, Byomkesh, Gargi, Jayanta, Kikira, Manik, Prodosh and Tapesh are going to Delhi from Kolkata
Logical Reasoning – Set 3: In an 8 X 8 chessboard a queen placed anywhere can attack another piece if the piece is present in the same row
Logical Reasoning – Set 4: A tea taster was assigned to rate teas from six different locations – Munnar, Wayanad, Ooty, Darjeeling, Assam and Himachal.
Logical Reasoning – Set 5: Four cars need to travel from Akala (A) to Bakala (B). Two routes are available, one via Mamur (M) and the other via Nanur (N).
Logical Reasoning – Set 6: A new airlines company is planning to start operations in a country.
Logical Reasoning – Set 7: In a square layout of size 5m × 5m, 25 equal sized square platforms of different heights are built.
Logical Reasoning – Set 8: There are 21 employees working in a division, out of whom 10 are special-skilled employees (SE) and the remaining are regular skilled employees (RE).
Logical Reasoning – Set 9: Healthy Bites is a fast food joint serving three items: burgers, fries and ice cream.
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