General Intelligence and Reasoning
The General Intelligence and Reasoning domain of AIIMS CRE checks how quickly you spot patterns and apply deductive rules, rather than how much you have memorised. Expect number and alphanumeric series, analogies, coding-decoding, syllogisms, blood relations, direction sense, ranking, seating puzzles, and non-verbal items such as mirror images, embedded figures and paper folding.
Core rules
- Series: test first differences, then ratios, then alternating or two-tier patterns. Keep squares, cubes and prime gaps in mind.
- Coding: write A–Z with positions; test +1, +2 and reverse (A=26) shifts; reverse the word before shifting if the code looks scrambled.
- Syllogism: draw minimal Venn diagrams. “All A are B” does not give “All B are A”; “Some A are B” is reversible, but a possibility conclusion needs a diagram where it can be true.
- Blood relations: build a family tree with clear symbols; never assume gender from a role such as doctor or teacher.
- Direction: track net displacement, then use Pythagoras for the shortest distance. Left and right swap when a person turns to face the opposite direction.
- Ranking: total = left rank + right rank − 1.
Worked example
Series: 3, 8, 15, 24, 35, ?. Differences are 5, 7, 9, 11 - consecutive odd numbers. The next difference is 13, so the answer is 35 + 13 = 48. Checking the second difference (2, 2, 2) confirms a quadratic pattern, not a random jump.
Traps that cost marks
Forcing a ratio pattern when differences already work; treating “some” as “all” in syllogism; guessing a person’s gender; forgetting that left/right reverses after a U-turn; and choosing a mirror image that flips letters which are not actually symmetric.