Analytical and Logical Reasoning
What this section tests
Two families. Logical reasoning: syllogisms, statement–assumption, strengthen/weaken, cause–effect, and course-of-action items. Analytical reasoning: seating and floor arrangements, blood relations, direction sense, coding–decoding, ranking, and number/letter series.
Concepts to master
Quantifiers - all, some, no, some not - and their Venn-diagram behaviour. For assumptions, the negation test. For series, check differences, ratios, alternating patterns, squares and primes. For direction sense, track net displacement with a sketch. For arrangements, draw a grid and fix one anchor clue first.
Traps that repeat
- Converse error: from all A are B you cannot infer all B are A.
- Some is symmetric (some A are B implies some B are A) but does not imply some A are not B unless the statement says so.
- Turning left or right reverses when a person faces south rather than north - always note the facing direction.
- Blood relations: never assume gender from a role word unless the clue states it.
- Which is NOT true items cost marks when the negative is missed.
Rule of thumb
For assumption questions, negate the candidate option. If the argument collapses under the negation, the option is a necessary assumption; if it survives, the option is not required. For syllogisms, draw the diagram that satisfies all premises and then look for a conclusion in every possible diagram - one counter-diagram kills the option.
Worked example
Premises: All pens are tools. Some tools are red. The tempting conclusion some pens are red fails: the red tools may all lie outside the pen set. Only some tools are pens is valid.