A four-generation chain — Blood Relations Aptitude Question
A four-generation chain: P is Q's brother, R is Q's mother, S is R's father and T is S's mother. Answer and worked solution on CodeKairo.
- Topic: Blood Relations
- Section: Logical Reasoning
- Difficulty: Hard
- Time target: 105 seconds
Question
P is Q's brother, R is Q's mother, S is R's father and T is S's mother. How is P related to T?
Options
- Grandson
- Great-grandson
- Son
- Nephew
Show the answer and the worked solution
Correct answer: B. Great-grandson
Worked solution
- R is Q's mother; S is R's father, so S is Q's grandfather.
- T is S's mother, so T is Q's great-grandmother.
- P is Q's brother, so T is P's great-grandmother too.
- P is T's great-grandson.
Answer: Great-grandson.
The idea
Draw the generations as a column, oldest at the top. Siblings sit on the same line, so what holds for one holds for the other.
Shortcut. Count the upward links from Q: mother (R), her father (S), his mother (T). Three steps up is a great-grandparent, and brother P shares every link.
Common trap. "Grandson" — counting only two links and stopping at S, the grandfather, instead of climbing one more step to S's mother T.