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Tricks to Solve Blood Relations Problems in Logical Reasoning

Thursday, October 22nd, 2020

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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 /Cousin
Wife of father	Mother	Daughter of son of grandmother/grandfather	Cousin/Oneself /Sister
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

• Based on statements/ conversations
• Based on puzzles
• Based on codes

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?

1. Mother
2. Aunt
3. Sister
4. Daughter
5. Grandmother

 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.

• Use vertical lines to represent parent-child relationships.
• Horizontal lines like <-> to denote marriages and dashed lines to represent sibling relationships. Apart from that, a sibling relationship can easily be established if they share the same root.
• You can also add gender differentiation to it by using a + sign for male and – sign for female.
• You can use (?) for the information that has not been provided to you.

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?

1. Mother
2. Sister-in-law
3. Sister
4. Mother-in-law
5. None of these

How is E related to C?

1. Daughter
2. Aunt
3. Cousin
4. Sister
5. Mother

Who is C to B?

1. Brother
2. Brother-in-law
3. Son-in-law
4. Nephew
5. None of these

How many male members are there in the family?

1. Two
2. Three
3. Four
4. Five
5. One

To solve such questions

• Read the data quickly. This would provide the feel of the problem.
• Separate the actual information, the usually stated information or the negative Information.
• Each of the actual information would give you some information that can be used to draw a part of the family tree. It is advisable, to begin with, a sentence that gives information about the parent-child relationship. Grandfather-grandson relationships and brother-sister relationships should be touched later.
• Go on reading actual information, one by one, and make diagrams for each of the information. These diagrams would be like parts or components of the final family tree. Simultaneously try not to draw additional tree diagrams for each new piece of information that you read. Instead, try adding information to the existing tree diagram on reading the new information. The usually stated information or negative info. Would be of immense use in this regard.
• Finally, with the help of all given info. etc. combine all the components into the final diagram.

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.

 

Example 2:

1. There are six person P, Q, R, S, T, and U in a family. They are a psychologist, Manager, Lawyer, Jeweler, Doctor, and Engineer.
2. The doctor is the grandfather of U who is a psychologist.

• The manager S is married to P.

1. R, the jeweler is married to the Lawyer.
2. Q is the mother of T and U.
3. There are two married couples in the family.

What is the profession of T?

1. Doctor
2. Jeweler
3. Psychologist
4. Manager
5. None of these

How’s P related to T?

1. Brother
2. Uncle
3. Grandfather
4. Father
5. None of these

How many male members are there in the family?

1. One
2. Two
3. Three
4. Four
5. Can’t be determined

What is the profession of P?

1. Doctor
2. Lawyer
3. Jeweler
4. Manager
5. None of these

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.

Sol 2:

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.

 

Other posts related to Logical Reasoning

How to Solve Number Series Questions in Logical Reasoning
How to solve Family Tree, Relationships problems based on coded symbols
Coded Inequality – Tips and Tricks to Solve Questions in Logical Reasoning
CAT Concepts – Introduction to Data Sufficiency
Basics of Data Interpretation – Approximation

CAT Questions related to Logical Reasoning

All questions from CAT Exam 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.

You can also see How to solve Family Tree, Relationships problems based on coded symbols

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