Logic and Analytical Reasoning
Logic and Analytical Reasoning tests valid inference, pattern recognition, and spatial or relational puzzles. Expect syllogisms, number and letter series, coding–decoding, directions, blood relations, and seating arrangements.
Core rules
- In a syllogism, a conclusion must follow from every possible arrangement of the premises.
- 'Some A are B' means at least one A is B; it does not mean some A are not B.
- In series, check differences, ratios, squares, and alternating patterns.
- In direction puzzles, draw axes and track turns; a left turn after facing north points west.
- In coding, test letter shifts and position values systematically.
Worked example
Premises: All poets are writers. Some writers are editors. Proposed conclusion: Some poets are editors. This is invalid. The editors who are writers may be outside the poet group. The middle term 'writers' is not distributed, so the conclusion cannot be forced. A valid conclusion would need 'All writers are editors' or a premise linking poets directly to editors.
Traps
- Affirming the converse: 'All A are B' does not mean 'All B are A'.
- Treating 'some' as 'some are not'.
- Assuming a conclusion that is only possible, not necessary.
- Losing direction after two or three turns.
- Forgetting that negative premises cannot yield a positive conclusion.