Logical Reasoning and Analytical Ability
Logical Reasoning and Analytical Ability tests structured thinking: syllogisms, blood relations, direction sense, coding–decoding, series, seating arrangement, statement–assumption and puzzles.
Core rules
- Syllogism: draw Venn diagrams for each premise and test whether the conclusion is true in every possible diagram. "All A are B" does not convert to "All B are A".
- Blood relations: draw a family tree; mark gender and generation; do not assume gender from a name or role.
- Direction sense: track net displacement on north–south and east–west axes; use Pythagoras for straight-line distance.
- Coding–decoding: compare letter positions and shifts before guessing a word pattern.
- Seating: fix one person and note facing direction; left and right reverse when a person faces south.
Worked example
Premises: "All constables are staff" and "Some staff are drivers." Conclusion: "Some constables are drivers." Draw a circle for constables inside staff, and a driver circle overlapping staff but not necessarily constables. The overlap between staff and drivers may lie outside the constable circle, so the conclusion is not guaranteed. It does not follow.
Traps
- Treating "some" as "all" or assuming a converse of "all A are B".
- Ignoring the possibility that two groups do not overlap.
- Reversing left and right when the row faces south.
- Forgetting that "either/or" conclusions require both possibilities to be exhaustive.
- In blood relations, missing that "brother's father" may be the speaker's father.
Write one diagram or tree for every puzzle before choosing an option.