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UGC NET · PAPER 2

UGC NET Paper 2 Computer Science – Unit 1: Discrete Structures and Optimization PYQ (December 2024)

8 questions · answer key at the end · updated 11 Oct 2026
Q7. Which one of the following is NOT a basic solution of the system of linear equations
x₁ + 2x₂ + x₃ = 4
2x₁ + x₂ + 5x₃ = 5
  1. x₁ = −1, x₂ = 2, x₃ = 1
  2. x₁ = 2, x₂ = 1 (x₃ = 0)
  3. x₁ = 5, x₃ = −1 (x₂ = 0)
  4. x₂ = 5/3, x₃ = 2/3 (x₁ = 0)
Answer & explanation →
Q14. Match List I with List II: match the logically equivalent propositions
List IList II
A. p → qI. (p ∧ q) ∨ (¬p ∧ ¬q)
B. ¬(p ∨ (¬p ∧ q))II. ¬p ∨ q
C. p ↔ qIII. ¬(p ∨ q)
D. ¬(p ↔ q)IV. ¬p ↔ q
  1. A-I, B-III, C-II, D-IV
  2. A-I, B-II, C-III, D-IV
  3. A-II, B-III, C-I, D-IV
  4. A-II, B-III, C-IV, D-I
Answer & explanation →
Q22. The probability that A hits a target is 1/4, and the probability that B hits the target is 2/5. Both shoot at the target. What is the probability that at least one of them hits the target, i.e., that A or B (or both) hit the target?
  1. 3/5
  2. 11/9
  3. 2/20
  4. 11/20
Answer & explanation →
Q40. If x and y are elements in a group G and if x⁵ = y³ = e, where e is the identity of G, then the inverse of x²yx⁴y² must be
  1. y²xy²x⁴
  2. yxy²x³
  3. yx⁶y⁶x³
  4. x⁴y²x²y
Answer & explanation →
Q58. Arrange the following graphs on the basis of number of edges in increasing order (for large n):
A. Kₙ (Complete Graph)
B. Cₙ (Cycle graph)
C. Wₙ (Wheel graph)
D. Kₙ,ₙ (Complete Bipartite Graph)
E. Qₙ (n-cube graph)
Choose the correct answer from the options given below:
  1. A, B, C, D, E
  2. B, C, A, D, E
  3. A, B, C, E, D
  4. E, D, C, A, B
Answer & explanation →
Q62. A linear programming problem (LPP) is as follows: Min z = 30x − 18y, subject to the constraints 3x + 4y ≤ 60, 5x − 3y ≥ 20 and x, y ≥ 0. In this feasible region, the solution(s) of the LPP is/are
A. (4, 0)
B. (2, 0)
C. (7, 5)
D. (0, 15)
E. (8, 5)
Choose the correct answer from the options given below:
  1. A and C only
  2. B only
  3. E only
  4. D only
Answer & explanation →
Q69. Which of the following graphs is/are planar?
Graph A (vertices a–f): edges ab, ac, bd, cf, de, ef, bf, cd.
Graph B (vertices a–f): edges af, ae, ad, ac, bf, bc, bd, ef, df, ce.
Graph C (vertices a–i): edges hi, hg, he, ia, if, ag, ae, ad, ab, bf, be, cf, cd, de, fg.
Choose the most appropriate answer from the options given below:
  1. A and C only
  2. B only
  3. A only
  4. A and B only
Answer & explanation →
Q89. Which of the following statements are true about sets?
A. 0 ∈ ∅
B. ∅ ∈ {0}
C. ∅ ∈ {∅}
D. {∅} ∈ {∅}
E. {∅} ⊂ {∅, {∅}}
Choose the correct answer from the options given below:
  1. A, B, C, D and E
  2. A, B, C and E only
  3. A, C only
  4. C and E only
Answer & explanation →

Answer key

  1. 7 – A
  2. 14 – C
  3. 22 – D
  4. 40 – B
  5. 58 – B
  6. 62 – A
  7. 69 – D
  8. 89 – D