Reasoning Ability: Puzzles, Syllogisms and Coded Logic
Reasoning Ability carries 20 questions in Phase I and is set at a moderate-to-tough level, with two or three full puzzle or seating-arrangement sets of five questions each. Around them sit syllogism, inequality, coding-decoding, blood relations, direction sense, order and ranking, alphanumeric series and data sufficiency.
Core rules
- In puzzles, start from the most restrictive definite clue (a fixed seat, a fixed floor, a direct name-place pairing), not from the first sentence. Draw a skeleton and record negative information ("X is not adjacent to Y") - it eliminates branches later.
- Syllogism: draw Venn diagrams. "All A are B" converts to "Some B are A"; "Some A are B" is already reversible. A conclusion follows only if it is true in every possible diagram.
- In inequality chains, combine only same-direction relations; if the conclusion needs a relation that the chain does not fix, it does not follow.
- In seating arrangements, note facing direction first - inward and outward facing reverse left and right.
Worked example
Statements: All banks are NBFCs. Some NBFCs are cooperatives. Conclusion I: Some banks are cooperatives - does not follow, because the cooperative NBFCs identified in the second statement need not be banks. Conclusion II: Some NBFCs are banks - follows, by conversion of "All banks are NBFCs".
Traps
- Selecting an "either-or" conclusion without checking that the two conclusions are complementary and individually undeducible.
- Missing the word "possibility" in a conclusion, which changes the test from certainty to consistency.
- Ignoring negative clues in a puzzle, then spending minutes on a branch that the clue had already killed.
- In blood relations, answering for the wrong person when the question asks "how is A related to B".