Reasoning / Mental Ability
Reasoning / Mental Ability
The reasoning paper tests series, analogies, coding-decoding, blood relations, direction sense, syllogism, seating arrangement, and non-verbal reasoning. Most questions are quick if you apply a fixed method rather than guessing.
Core rules and concepts
- Number series: check consecutive differences first, then ratios; look for squares, cubes, and alternating or double-difference patterns.
- Coding-decoding: write the alphabet with positions A=1 to Z=26; test shift patterns and reverse positions (A↔Z, B↔Y).
- Blood relations: draw a tree and use clear symbols for male/female; never assume gender from a relationship word.
- Direction sense: draw a compass, fix north, and track left/right turns; net displacement uses Pythagoras.
- Syllogism: draw Venn diagrams; "all A are B" does not imply "all B are A"; "some" statements are reversible.
- Seating: place fixed clues first, then eliminate.
Worked example
Find the next term: 3, 8, 18, 38, 78, ?. Differences are 5, 10, 20, 40, which double each time, so the next difference is 80. Next term = 78 + 80 = 158.
Traps
Do not assume a person faces north unless stated. In syllogism, avoid converting "all" into "some" incorrectly. In series, a single pattern may not fit - test two rules before answering. In blood relations, do not treat "brother of my uncle" as automatically meaning a cousin without checking the family tree.