Logical Reasoning
Logical Reasoning
KMAT's logical reasoning domain covers syllogisms, seating and linear arrangements, blood relations, direction sense, number and letter series, coding-decoding, statement-assumption and course-of-action questions. The test is deductive: you must use only the information given, not real-world likelihood.
Core rules and concepts
- All A are B converts to Some B are A. No A are B converts to No B are A. Some A are B converts to Some B are A.
- Some A are not B is not implied by Some A are B. Draw Venn diagrams for three-statement syllogisms.
- In arrangements, fix definite positions first, then apply negative clues. Do not assume unstated genders, directions or order.
- In direction questions, draw north-south and east-west axes and calculate net displacement.
- In series, check differences, ratios, squares, cubes and alternating patterns before assuming a single rule.
Worked example
Statements: All pens are books. Some books are red.
Conclusions: I. Some pens are red. II. Some books are pens.
Only II follows. All pens are books means every pen lies inside the books set, so at least some books are pens. The red books may be outside the pens subset, so conclusion I is not guaranteed. This is the classic error of linking two statements through a shared middle term without checking overlap.
Traps that cost marks
Illicit conversion is the most frequent mistake: All A are B does not mean All B are A. Do not read Some as meaning some but not all. Avoid using general knowledge to reject a valid deduction. In arrangement puzzles, an option that is merely possible is not the same as one that must be true.