Reasoning and Mental Ability: Patterns, Relations and Deduction
Reasoning and Mental Ability tests logical structure rather than factual recall. Common items include number and letter series, analogies, coding-decoding, blood relations, directions, syllogisms, seating arrangement, ranking, calendars and non-verbal figures.
Core methods
- Series: check differences, then second differences; also test multiplication, squares, cubes and alternating patterns.
- Coding: convert letters to positions (A = 1 … Z = 26) and look for shifts, reversals or word-based rules.
- Blood relations: draw a family tree and mark gender and generation; do not assume a relation that is not stated.
- Directions: sketch every turn on paper; track facing direction separately from movement direction.
- Syllogism: draw minimal Venn diagrams. “All A are B” does not imply “All B are A”; “some A are B” does not imply “some A are not B”.
Worked example
Find the next term: 3, 8, 15, 24, ?. The differences are 5, 7 and 9, increasing by 2. The next difference is 11, so the next term is 24 + 11 = 35. A second check shows the terms are 2² − 1, 3² − 1, 4² − 1, 5² − 1, so the next is 6² − 1 = 35. Two independent patterns confirming the same answer is a good sign.
Traps that cost marks
In blood relations, “brother of my father’s sister” may be the father, not an uncle, depending on the exact wording. In directions, a left turn after facing south changes the facing direction, not the starting point. In syllogism, avoid adding real-world knowledge; use only the statements. In seating puzzles, confirm whether people face the centre or outside.
Exam habit
Write small diagrams; most reasoning errors are tracking errors, not conceptual gaps.