Reasoning and Mental Ability
Reasoning and Mental Ability tests logical speed rather than a syllabus: series, analogy, coding–decoding, blood relations, direction sense, ranking, syllogism, Venn diagrams, seating arrangement, dice and cubes, mirror and water images.
Core rules
- Alphabet position: A=1 to Z=26. Memorise the EJOTY cluster (E=5, J=10, O=15, T=20, Y=25) and the opposite pairs summing to 27 (A–Z, B–Y, M–N).
- Number series: test differences first, then ratios, then squares, cubes and alternating patterns.
- Blood relations: draw a small family tree; use '+' for male, '−' for female, horizontal for siblings and vertical for parent–child.
- Direction sense: fix north upwards, track turning angles, and use Pythagoras for net displacement.
- Syllogism: only the given statements count; a "possibility" conclusion fails only if a counter-example exists.
Worked example
If FRIEND is coded as HTKGPF, how is CANDLE coded? Compare F→H (+2) and R→T (+2), so every letter shifts two places forward. Then C→E, A→C, N→P, D→F, L→N, E→G, giving ECPFNG. Always confirm the rule on the second and third letters, since a single match can be coincidence.
Traps
- Assuming the shift is always forward; check for a −1, reversal or mirror pattern.
- In seating puzzles, forgetting to reverse left and right when people face south.
- In cube problems, counting painted faces instead of painted small cubes.
- In blood relations, missing the gender hinted by a single word such as "his" or "her".