Blood Relations

In blood relation problems, that are often asked in analytical/logical reasoning section of competitive exams, a chain of relations is given and based on that information we are asked to identify the relationship between any two members.

Relations from Paternal (Father’s) Side

1. Father’s father -> Grandfather
2. Father’s mother -> Grandmother
3. Father’s brother -> Uncle
4. Father’s sister -> Aunt
5. Wife of uncle -> Aunt
6. Husband of aunt-> Uncle
7. Children of uncle or aunt -> Cousin

Relations from Maternal (Mother’s) Side

1. Mother’s father -> Maternal Grandfather
2. Mother’s mother -> Maternal Grandmother
3. Mother’s brother -> Maternal uncle
4. Mother’s sister -> Maternal Aunt
5. Children of maternal uncle -> Cousin
6. Wife of maternal uncle -> Maternal aunt

Other Relations

1. Grandfather’s or Grandmother’s son -> Father or Uncle
2. Grandfather’s or Grandmother’s only son -> Father
3. Mother’s or father’s son -> Brother
4. Mother’s or father’s daughter -> Sister
5. Son’s wife -> Daughter-in-law
6. Husband’s or wife’s sister -> Sister-in-law
7. Daughter’s husband -> Son-in-law
8. Husband’s or wife’s brother -> Brother-in-law
9. Brother’s son -> Nephew
10. Brother’s daughter -> Niece
11. Sister’s husband -> Brother-in-law
12. Brother’s wife -> Sister-in-law
13. Grandson’s or Grand daughter’s daughter -> Great grand daughter

Examples

Example. 1 Introducing Minisha to guests, Rohit said, “Her father is the only son of my father.” How is Minisha related to Rohit?
(a) Daughter
(b) Mother
(c) Sister
(d) Niece

Ans: (a)
Explanation: The only son of Rohit’s father is Rohit himself. This means that Rohit is the father of Minisha. Hence, Minisha is the daughter of Rohit.

Example. 2 Looking at a photograph, Abhishek said, “His mother is the wife of my father’s only son.” At whose photograph was Abhishek looking?
(a) Cousin
(b) Son
(c) Father
(d) Nephew

Ans: (b)
Explanation: My father’s only son means me, i.e., Abhishek
Now, wife of my father’s only son means my wife, i.e., Abhishek’s wife
So, Abhishek’s wife is the mother of the person in the photograph hence Abhishek is the father of the person in the photograph.
Therefore, the person in the photograph is his Son.

Example. 3 If ‘A + B’ means that A is the brother of B, ‘A ÷ B’ means that A is the father of B and ‘A × B’ means that A is the sister of B. Which of the following means ‘M’ is the uncle of ‘P’?
(a) M ÷ N × P
(b) N × P ÷ M
(c) M + S ÷ R + P
(d) M + K ÷ T × P

Ans: (d)
Explanation:
T × P means ‘T’ is the sister of ‘P’
K ÷ T means ‘K’ is the father of ‘T’, hence ‘K’ is also the father of ‘P’
M + K means ‘M’ is the brother of ‘K’, therefore, ‘M’ is the uncle of ‘P’

Example. 4 Pointing to a photograph, Avinash said, “She is the daughter of my grandfather’s only son.” How is Avinash related to the girl in the photograph?
(a) Father
(b) Brother
(c) Husband
(d) Uncle

Ans: (b)
Explanation: My Grandfather’s only Son means my Father.
Hence, the girl in the photograph is the daughter of Avinash’s father i.e., Avinash is the girl’s brother.

Example. 5 If P – Q means Q is son of P, P × Q means P is brother of Q, P ÷ Q means Q is sister of P and P + Q means P is mother of Q.
If N × K – M ÷ L, then which of the following is definitely true ?

(a) K is father of L and M
(b) L is daughter of K and niece of uncle N
(c) K is father of L and M – his son and daughter respectively
(d) M is uncle of K’s brother N

SNAP 2013

Ans: (b)
Explanation:
M ÷ L means L is sister of M
K – M means M is son of K, hence L is daughter of K
N × K means N is brother of K, hence N is uncle of L
Therefore, L is daughter of K and niece of uncle N

Example. 6 Read the following information to answer the question that follows.
P – Q means Q is father of P
P × Q means Q is brother of P
P ÷ Q means Q is wife of P
P + Q means Q is sister of P
Which of the following means M is the grandfather of T?

(a) T – C ÷ L + N × M
(b) T – R ÷ Z + L × M
(c) T ÷ Z × L + F – M
(d) None of these

IIFT 2013

Ans: (d)
Explanation:
Option 1:
M is the brother of N, who is the sister of L So, M is also the brother of L. L is the wife of C who is the father of T. Thus, M cannot be the grandfather of T.
Option 2:
M and T are at the same position in option 2 as in 1. Also, since the symbols and their position in option 2 is the same as that in option 1, the relation between the two is also the same.
Option 3:
M is the father of F who is the sister of L. L is the brother of Z. Thus, M is the father of F, L and Z. Z is the wife of T. Thus M cannot be the grandfather of T.

Thus, none of the given options means M is the grandfather of T.
Hence, Option 4 is the correct answer.