Module 1 · SBI Clerk Reasoning Ability
Blood Relations
Family trees, coded relations, generation gap.
Family Trees · Coded Relations · Generation Gap
Learning Objectives
- Understand the fundamental concepts of Blood Relations
- Apply key formulas and techniques to solve problems
- Practice with exam-level questions to build speed and accuracy
Key Concepts
What are Blood Relations?
Blood relation questions test your ability to understand family relationships and genealogical connections. You are given descriptions of relationships between family members and must answer questions about how two individuals are related. These questions appear regularly in SSC CGL Tier 1 exams.
Key Relationships to Remember
- Father/Mother: Parent of the person.
- Brother/Sister: Sibling (same parents).
- Husband/Wife: Spouse.
- Son/Daughter: Child.
- Grandfather/Grandmother: Parent's parent.
- Uncle/Aunt: Parent's brother/sister or spouse's sibling.
- Cousin: Child of uncle/aunt.
- Nephew/Niece: Child of sibling.
- Father-in-law/Mother-in-law: Spouse's parent.
- Brother-in-law/Sister-in-law: Spouse's sibling or sibling's spouse.
Solved Examples
Example 1 (Direct Relation)
A is the father of B. C is the daughter of B. D is the brother of C. How is A related to D?
a) Grandfather b) Father c) Uncle d) Cousin
a) Grandfather b) Father c) Uncle d) Cousin
Solution: a) Grandfather. A → B (father). B → C (daughter), so B is C's parent. D is C's brother, so D is also B's child. Therefore, A is D's grandfather (parent's parent).
Example 2 (Coded Relation)
If 'P + Q' means P is the father of Q, 'P - Q' means P is the mother of Q, 'P × Q' means P is the brother of Q, and 'P ÷ Q' means P is the sister of Q, then what does 'A + B - C' mean?
a) A is the grandfather of C b) A is the father of C c) A is the uncle of C d) Cannot be determined
a) A is the grandfather of C b) A is the father of C c) A is the uncle of C d) Cannot be determined
Solution: a) A is the grandfather of C. A + B means A is father of B. B - C means B is mother of C. So A is the father of B, who is the mother of C. Hence A is the maternal grandfather of C.
Example 3 (Generation Gap)
A is the sister of B. B is the mother of C. C is the brother of D. D is the wife of E. How is A related to E?
a) Mother-in-law b) Sister-in-law c) Aunt d) Grandmother
a) Mother-in-law b) Sister-in-law c) Aunt d) Grandmother
Solution: b) Sister-in-law. A is B's sister. B is C's mother. C is D's brother, so C and D are siblings. D is E's wife. So A is the sister of B, who is the mother of C (and D). A is D's aunt. D is married to E. So A is the aunt of E's wife — in relationship terms, A is E's aunt by marriage = sister-in-law. Actually: A is the sister of B, B is mother of C and D (since C and D are siblings), so A is maternal aunt of D. D is married to E. So A is the aunt of E's wife = no direct relation. Actually: A is sister-in-law of E because A is the sister of B (who is the mother of D, who is E's wife). So A is the sister of B, who is D's mother. D is E's wife. A has no direct relation to E. But through D: A is D's maternal aunt, so A is the aunt of E's wife. In common terms, A is E's aunt. Among options: Sister-in-law (wife's aunt is not sister-in-law), Mother-in-law (no), Aunt (yes, by marriage), Grandmother (no). So answer: c) Aunt.
Shortcut Techniques
- Always draw a family tree with horizontal lines for marriage (=) and vertical lines for parent-child (|). Write names and relationships as you read.
- Use generation counting: assign +1 to each older generation, 0 to same generation, -1 to younger generation. Add the gaps.
- For coded relations (+ - × ÷), solve step by step from left to right, keeping track of who is who.
Pro Tip
In coded relation problems, always start from the last expression. For 'A + B - C', first find B-C relationship, then A with that result. Also, gender matters — if A is father of B, A is male. Track genders carefully.
Advanced Problem Types
Competitive exams feature advanced variations combining multiple reasoning concepts. Master these to score high.
Multi-Step Problems
Some questions require applying multiple reasoning techniques sequentially. Break problems into clear steps.
Common Traps
- Assuming a pattern continues without checking all elements
- Misinterpreting negative statements in syllogisms
- Forgetting wrapping in alphabet coding (Z to A transition)
- Confusing directions (East vs West)
- Overlooking either-or cases in syllogisms
- Not considering all possible arrangements in puzzles
Pro Tip
For puzzles, start with the most concrete clue and build around it. Draw diagrams for seating arrangements and family trees for blood relations.
Advanced Problem Types
Competitive exams feature advanced variations combining multiple reasoning concepts. Master these to score high.
Multi-Step Problems
Some questions require applying multiple reasoning techniques sequentially. Break problems into clear steps.
Common Traps
- Assuming a pattern continues without checking all elements
- Misinterpreting negative statements in syllogisms
- Forgetting wrapping in alphabet coding (Z to A transition)
- Confusing directions (East vs West)
- Overlooking either-or cases in syllogisms
- Not considering all possible arrangements in puzzles
Pro Tip
For puzzles, start with the most concrete clue and build around it. Draw diagrams for seating arrangements and family trees for blood relations.
Advanced Problem Types
Competitive exams feature advanced variations combining multiple reasoning concepts. Master these to score high.
Multi-Step Problems
Some questions require applying multiple reasoning techniques sequentially. Break problems into clear steps.
Common Traps
- Assuming a pattern continues without checking all elements
- Misinterpreting negative statements in syllogisms
- Forgetting wrapping in alphabet coding (Z to A transition)
- Confusing directions (East vs West)
- Overlooking either-or cases in syllogisms
- Not considering all possible arrangements in puzzles
Pro Tip
For puzzles, start with the most concrete clue and build around it. Draw diagrams for seating arrangements and family trees for blood relations.
Advanced Problem Types
Competitive exams feature advanced variations combining multiple reasoning concepts. Master these to score high.
Multi-Step Problems
Some questions require applying multiple reasoning techniques sequentially. Break problems into clear steps.
Common Traps
- Assuming a pattern continues without checking all elements
- Misinterpreting negative statements in syllogisms
- Forgetting wrapping in alphabet coding (Z to A transition)
- Confusing directions (East vs West)
- Overlooking either-or cases in syllogisms
- Not considering all possible arrangements in puzzles
Pro Tip
For puzzles, start with the most concrete clue and build around it. Draw diagrams for seating arrangements and family trees for blood relations.
Sample family tree showing relationships between family members