Logical Reasoning
What TANCET tests here
Logical Reasoning covers syllogisms, blood relations, direction sense, seating and floor arrangements, coding-decoding, number and letter series, Venn diagrams, and verbal-critical items such as assumptions, conclusions and strong versus weak arguments. Most questions are solvable by a fixed procedure; accuracy depends on representing information cleanly.
Core rules
- Syllogisms: draw the minimum Venn diagram that satisfies the statements. A conclusion follows only if it is true in every diagram; 'some' does not imply 'all', and 'some A are B' converts to 'some B are A'.
- Blood relations: draw a family tree with gender marked; never reverse a relation ('A is B's father' does not make B the father).
- Direction sense: fix north and track net displacement; use Pythagoras for shortest distance.
- Seating: start with the most constrained clue; distinguish 'left of' from 'immediate left'.
- Coding-decoding: test letter shifts, reversal and position sums before guessing.
- Arguments: a strong argument must be relevant to the stated issue and must follow from the given facts, not from personal opinion.
Worked example
Statements: All analysts are planners. Some planners are coders. Conclusions: (I) Some analysts are coders. (II) Some coders are planners. Draw planners as a large circle containing analysts; place a coders circle overlapping planners but not necessarily analysts. Conclusion I is not forced - the coder-planner overlap may lie outside the analyst subset. Conclusion II is the valid conversion of 'Some planners are coders'. Only II follows.
Traps that cost marks
- Treating a possible conclusion as a certain one.
- Assuming every element in a seating puzzle is mentioned explicitly.
- Reversing subject and object in blood-relation statements.
- Ignoring 'only', 'at least' and 'all but' qualifiers.
- In assumption questions, choosing a restatement of the argument instead of an unstated premise.