UGC NET Questions (Paper – 1)

Proof by contrapositive exploits the logical equivalence between a conditional and its contrapositive. Instead of proving "if p, then q" directly, one proves "if not q, then not p". Because these two statements share the same truth conditions, demonstrating the contrapositive suffices to establish the original conditional. Thus the method described is called proof by contrapositive.

Option A:
Option A, proof by cases, involves dividing a problem into exhaustive possibilities and proving the desired conclusion in each case. While also a valid strategy, it does not focus on transforming a conditional into its contrapositive. Hence cases is not correct.

Option B:
Option B, proof by contradiction, proceeds by assuming the negation of what is to be proved and deriving a contradiction, thereby showing the assumption must be false. This is a distinct method and does not necessarily proceed via contrapositive structure.

Option C:
Option C is correct because proof by contrapositive explicitly names the strategy of proving the contrapositive to justify the original "if p, then q". It leverages the equivalence relation discussed earlier and is particularly useful when the direct approach is difficult.

Option D:
Option D, proof by example, at most shows that a statement is true in one or some instances and is usually insufficient to establish universal claims. It does not relate to the contrapositive transformation.

Statements A and B describe systematic coding and how multiple examples reveal the pattern. Statement D is also correct because many codes use alphabet positions, sums or reversals. Statement C is false since one example can match many different rules, and E is false because solving requires pattern detection, not guessing. Hence A, B and D only are correct.

Option A:
Option A is incomplete because it omits D (common operations), so it does not include all true statements.

Option B:
Option B is correct as it includes all true statements and excludes C and E, both of which are false.

Option C:
Option C is wrong because it includes C (false) and omits A (basic description).

Option D:
Option D is wrong because it includes C (false) and omits B (need multiple examples), so it cannot be correct.

A, B, D and E are sound strategies; C is wrong because assuming something that contradicts given conditions makes the reasoning invalid and can only mislead. Therefore C alone is the wrong statement.

Option A:
Option A is correct because it singles out only C as incorrect and keeps the standard strategies intact.

Option B:
Option B is incorrect because it wrongly treats A as wrong; A is a standard elimination method.

Option C:
Option C is incorrect because it wrongly includes D as wrong; eliminating impossible options does improve chances in MCQs.

Option D:
Option D is incorrect because it wrongly treats B as wrong; combining clues is essential in such puzzles.

Statements A, B and D describe genuine features of letter series. A is correct because positions like A=1, B=2 are routinely used to detect shifts. B is true since many series move letters by a fixed pattern that repeats. D is also correct because repeated blocks such as ABCABC suggest a repeating cycle whose length is diagnostic. C is false because there is no requirement that vowels and consonants alternate, and E is false as alternate positions can follow a second rule, so A, B and D only are correct.

Option A:
Option A is incomplete since it leaves out D. Without checking repeating blocks, the strategy for handling many cyclic letter series is not fully described, so A and B alone do not constitute the entire correct set.

Option B:
Option B is correct because it gathers the alphabet-position idea, cyclic shifts and block detection, all of which are central to solving letter series, and excludes C and E, which over-restrict possible patterns.

Option C:
Option C is wrong as it includes E, claiming that two rules cannot govern alternate positions, which is directly contradicted by many exam examples, and it omits B, losing an important cyclical feature.

Option D:
Option D is incorrect because it accepts E and drops A, thereby discarding the basic alphabet-position tool while also denying multi-rule patterns, so it cannot represent the set of correct statements.

Statement A summarises how analogy questions require transferring a discovered relation from one pair to another. Statement B notes that the relation can take many forms such as part–whole or cause–effect. Statement E is also correct because understanding the type of relation is central to answering analogies, even though word meanings are also needed. Statement C is false since in classification the odd item out is the one that does not fit the common pattern, and D is false because NET papers can mix verbal and non-verbal analogies. Thus A, B and E only are correct, matching option A.

Option A:
Option A is correct as it highlights the relational nature of analogies, the variety of possible connections and the strategic focus on identifying relationships, while excluding C and D, which misdescribe classification and exam design.

Option B:
Option B is incorrect because it includes C, which reverses the idea of an odd item out, and it omits E, so it both accepts a false statement and loses an important strategic insight.

Option C:
Option C is wrong since it includes D, which wrongly claims that verbal and non-verbal analogies never appear together, and it omits B, thereby weakening the explanation of relation types.

Option D:
Option D is incorrect because it contains C, the wrong description of the odd item, and it fails to include A, so it both introduces an error and omits a core feature of analogies.

Statement D is the only wrong statement here. A is correct because typical classification sets have three similar items and one different item. B is true since the task is to find the item that does not fit the pattern. C is correct; number properties like odd/even or prime/composite are common grouping criteria. E is also true because when multiple properties are present, the dominant common property helps determine the odd one out. D is false since familiarity to the candidate has nothing to do with correctness; the odd item is defined by the underlying property.

Option A:
Option A is incorrect as it groups B with D as wrong, even though B correctly states the central objective of classification questions.

Option B:
Option B is wrong because it treats A as wrong, but A accurately describes the common “three similar, one different” structure.

Option C:
Option C is incorrect since it labels C as wrong even though number-based classification commonly uses parity/divisibility/primality, and it still includes D; the wrong set is not “C and D”.

Option D:
Option D is correct because it singles out D (familiarity-based) as the only incorrect statement while accepting the other accurate descriptions of classification reasoning.

A, B, C and E correctly describe data sufficiency structure and skills. D is false because the stem defines what “sufficient” means; ignoring it leads to wrong sufficiency judgments. Thus A, B, C and E only are correct.

Option A:
Option A is correct because it includes all true statements and excludes D (false strategy).

Option B:
Option B is incomplete because it omits E (careful reading of constraints).

Option C:
Option C is incorrect because it includes D (false).

Option D:
Option D is incorrect because it omits B (core “alone vs together” logic) and includes D (false).