Blood Relations Basics
Comprehensive guide to solving Blood Relations problems in logical reasoning. Learn paternal and maternal relationships, important family connections, problem-solving strategies with step-by-step solved examples from competitive exams. Master coded relationship problems with symbols and avoid common mistakes.
In blood relation problems, commonly found in analytical/logical reasoning sections of competitive exams, you are given a chain of relationships between family members. Based on this information, you need to identify the relationship between any two specific members.
Key Approach: Break down complex statements step by step, identify the speaker's relationship to intermediate persons, and then determine the final relationship.
Relations from Paternal (Father's) Side
- Father's father → Grandfather
- Father's mother → Grandmother
- Father's brother → Uncle
- Father's sister → Aunt
- Wife of uncle → Aunt
- Husband of aunt → Uncle
- Children of uncle or aunt → Cousin
Relations from Maternal (Mother's) Side
- Mother's father → Maternal Grandfather
- Mother's mother → Maternal Grandmother
- Mother's brother → Maternal Uncle
- Mother's sister → Maternal Aunt
- Children of maternal uncle → Cousin
- Wife of maternal uncle → Maternal Aunt
Other Important Relations
- Grandfather's or Grandmother's son → Father or Uncle
- Grandfather's or Grandmother's only son → Father
- Mother's or Father's son → Brother
- Mother's or Father's daughter → Sister
- Son's wife → Daughter-in-law
- Husband's or Wife's sister → Sister-in-law
- Daughter's husband → Son-in-law
- Husband's or Wife's brother → Brother-in-law
- Brother's son → Nephew
- Brother's daughter → Niece
- Sister's husband → Brother-in-law
- Brother's wife → Sister-in-law
- Grandson's or Granddaughter's daughter → Great-granddaughter
Step 1: Identify who is speaking (the reference person)
Step 2: Start from the reference person and work through the relationships one at a time
Step 3: Pay special attention to phrases like "only son" or "only daughter" - these are crucial clues
Step 4: Draw a simple family tree diagram if the relationship chain is complex
Solved Examples
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.
• 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'
Hence, the girl in the photograph is the daughter of Avinash's father, i.e., Avinash is the girl's brother.
If N × K - M ÷ L, then which of the following is definitely true?
• 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
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?
Option 2: M and T are at the same position in option 2 as in option 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.
Key Points to Remember
- "Only son" or "Only daughter" is a critical phrase - it means the speaker is referring to themselves or has no siblings
- Always start from the reference person (usually the speaker) and work step by step
- In coded relationship problems, carefully decode each symbol before establishing the final relationship
- Watch for gender clues in the question - pronouns like "his" or "her" provide important information
- When analyzing options, systematically check each one by breaking down the relationship chain
- Drawing a simple family tree can help visualize complex relationships
- Remember: Uncle = Father's or Mother's brother; Aunt = Father's or Mother's sister
1. Missing "only": Don't overlook words like "only son" or "only daughter" - they significantly change the relationship
2. Gender confusion: Pay attention to pronouns (he/she, his/her) to correctly identify gender
3. Rushing through coded problems: In symbol-based questions, decode each relationship carefully before combining them
4. Assuming relationships: Don't assume a relationship exists - work through the given information systematically
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