UTpaper

Free mock tests & test series

Question 4Asked in UGC NET Computer Science, June 2015 (Paper II & III, Selected Questions)

Match the following : List–I

Match the following : List–I (a) (p→q) ⇔ (¬q→¬p) (b) [(p∧q)→r] ⇔ [p→(q→r)] (c) (p→q) ⇔ [(p∧¬q)→0] (d) (p↔q) ⇔ [(p→q) ∧ (q→p)] List–II (i) Contrapositive (ii) Exportation law (iii) Reductio ad absurdum (iv) Equivalence Codes : a b c d
  1. A(i) (ii) (iii) (iv)
  2. B(ii) (iii) (i) (iv)
  3. C(iii) (ii) (iv) (i)
  4. D(iv) (ii) (iii) (i)
Show answerHide answer

Correct answer: (A) (i) (ii) (iii) (iv)

Explanation

(a) Contrapositive: negate both hypothesis and conclusion and interchange them: (p → q) ⇔ (¬q → ¬p). (b) Exportation is a valid rule of replacement: ((p ∧ q) → r) ⇔ (p → (q → r)). (c) Reductio ad absurdum: (p → q) ⇔ [(p ∧ ¬q) → 0]. (d) Equivalence (biconditional): (p ↔ q) ⇔ (p → q) ∧ (q → p). So a-(i), b-(ii), c-(iii), d-(iv).

From UGC NET Computer Science PYQ, June 2015 (Paper II & III, Selected Questions)

This is question 4 of UGC NET Computer Science PYQ, June 2015 (Paper II & III, Selected Questions). See all questions of this paper with answers, or attempt the paper as a timed online test to get your score and all-India rank.