Reasoning and Mental Ability
Domain 4 - Reasoning and Mental Ability
Verbal and non-verbal reasoning: series, analogy, classification, coding–decoding, blood relations, direction sense, ranking, syllogism, clocks and calendars, mirror and embedded figures.
Core tools
- Alphabet positions: learn EJOTY (E = 5, J = 10, O = 15, T = 20, Y = 25) to locate any letter instantly.
- Series: check differences first, then ratios, then squares/cubes, then alternating patterns.
- Coding: write the alphabet with numbers above it, then compare letter by letter to find the shift.
- Blood relations: draw a family tree with + for male, − for female, and horizontal lines for siblings and marriage.
- Direction sense: fix north at the top; use Pythagoras for the shortest distance.
- Syllogism: a conclusion is valid only if it holds in every possible Venn diagram of the premises.
Worked example
If MOBILE is coded as NPCJMF, how is PHONE coded? Compare letters: M→N, O→P, B→C, I→J, L→M, E→F. Each letter moves one step forward. Apply the same shift: P→Q, H→I, O→P, N→O, E→F. Answer: QIPOF.
Traps that cost marks
- Counting positions 'between' two people as inclusive when the question says 'between'.
- Ignoring the reverse alphabet (A = 26) in mixed series.
- In syllogism, assuming a possibility as a definite conclusion.
- In blood relations, forgetting that 'my father's only son' may be the speaker himself.
- Misreading left/right after a turn - always re-orient from the person's facing direction.