Reasoning: Puzzles, Deduction and Speed
What the reasoning section tests
The IBPS RRB PO reasoning paper is a speed-and-accuracy test built on puzzles and deductive rules. Prelims carries 40 questions for 50 marks inside a 45-minute combined window with Quantitative Aptitude; Mains also has 40 questions for 50 marks. Expect seating arrangement, floor/flat puzzles, box puzzles, syllogism, inequality, coding-decoding, blood relations, direction sense, order-ranking, alphanumeric series and data sufficiency.
Core rules to internalise
- In circular seating, left and right reverse when a person faces outside. Fix one person and propagate.
- For row ranking, total = left rank + right rank - 1. Number between two people = difference in positions - 1.
- Syllogism: 'some A are B' is reversible; 'all A are B' is not reversible. A conclusion is false only when a valid Venn arrangement contradicts it.
- Inequality: 'either-or' needs a complementary pair such as A ≥ B and A < B, with the same subjects.
- Blood relations: draw a tree and mark gender only when stated. Do not infer gender from a name.
Worked example
In a row of 40 students, A is 12th from the left and B is 17th from the right. How many students sit between them? B's position from the left = 40 - 17 + 1 = 24. A is at 12. Number between = 24 - 12 - 1 = 11. The subtraction of 1 removes B from the count.
Traps that cost marks
Treating 'only a few' as ordinary 'some'; reversing 'all' statements; forgetting the facing-direction flip; spending more than two minutes on a single puzzle; and choosing a conclusion that is merely possible when the question asks what definitely follows.