General Intelligence and Reasoning Ability: Series, Coding, Relations and Syllogism
General Intelligence and Reasoning Ability tests how quickly you spot a rule rather than how much you remember. DSSSB TGT items are largely verbal - series, analogies, coding–decoding, blood relations, direction sense, syllogism, ranking and seating - plus non-verbal items on mirror images, embedded figures, paper folding and dice, which are described in the paper itself.
Rules to hold
- Number series: test differences first, then ratios, then squares and cubes, then alternating series, then digit sums.
- Coding–decoding: align word and code letter by letter; note constant shifts (+1, −2), reversal, and A=1…Z=26 values. Opposite letters always sum to 27 (A–Z, B–Y, C–X).
- Blood relations: draw the family tree immediately and mark gender symbols, so gender questions cannot trap you.
- Direction sense: fix one axis before rotating - facing north, a left turn takes you west.
- Syllogism: draw Venn circles; a conclusion is valid only if it holds in every possible diagram.
Worked example
If MADRAS is coded as NBESBT, how is BOMBAY coded? Compare the pairs: M→N, A→B, D→E. Each letter moves one step forward. Applying the same shift: B→C, O→P, M→N, B→C, A→B, Y→Z. Answer: CPNCBZ. If the shift looks irregular, check whether the word is reversed before shifting.
Traps
- "Only son of my mother" fixes gender; "son of my mother" does not.
- "All A are B" never implies "All B are A".
- In ranking, total = (position from left + position from right) − 1.
- The first difference in a series often looks constant across only two terms.