Relations written as symbols — Aptitude Question
Relations written as symbols: If A + B means A is the mother of B and A × B means A is the sister of B, what does P… Answer and worked solution on CodeKairo.
- Topic: Blood Relations
- Section: Logical Reasoning
- Difficulty: Medium
- Time target: 75 seconds
Question
If A + B means A is the mother of B and A × B means A is the sister of B, what does P + Q × R mean?
Options
- P is the mother of R
- P is the sister of R
- P is the aunt of R
- P is the grandmother of R
Show the answer and the worked solution
Correct answer: A. P is the mother of R
Worked solution
- P + Q: P is the mother of Q.
- Q × R: Q is the sister of R, so Q and R have the same parents.
- Therefore P is also R's mother: P is the mother of R.
Answer: P is the mother of R.
The idea
Translate each symbol into a sentence, then combine. A sibling link passes a parent relation across to the sibling.
Shortcut. × (sister) keeps the generation, so the mother of Q is also the mother of Q's sibling R: P is the mother of R.
Common trap. "P is the sister of R" — reading only the last symbol, ×, and taking its meaning as the whole relation.