General Intelligence and Reasoning Ability: Rules and Traps
What the domain tests
General Intelligence and Reasoning Ability checks whether you can find a rule and apply it under time pressure. DSSSB JE items usually cover series (number, letter, figure), analogies, coding–decoding, blood relations, direction sense, syllogism, seating arrangement, ranking and non-verbal reasoning (mirror image, paper folding, embedded figures).
Core rules
- Series: test differences, then ratios, then alternating or square/cube patterns; do not settle on the first difference.
- Coding: write the alphabet with positions 1–26; check forward, backward and positional-sum codes separately.
- Syllogism: a conclusion must be true in every possible diagram. 'Some A are B' does not imply 'some B are not A'.
- Blood relations: draw a family tree; never assign gender from a relation word alone except mother/father/son/daughter.
- Direction: fix north and track left/right turns; a left turn after facing south means east.
Worked example
Find the next term: 2, 6, 12, 20, 30, ? Differences are 4, 6, 8, 10, so the next difference is 12 and the term is 42. A second check is n(n+1): 1×2, 2×3, 3×4, 4×5, 5×6, 6×7 = 42. Answer: 42.
Traps
Assuming a series is arithmetic after two terms; ignoring the reversal step in coding; accepting a syllogism conclusion that is only 'possible'; mixing 'father's sister' with 'mother's sister'; and in seating puzzles, forgetting that 'left' depends on the direction each person faces.