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UGC NET · PAPER 2

UGC NET Paper 2 Computer Science – Unit 1: Discrete Structures and Optimisation PYQ (22 June 2026)

16 questions · answer key at the end · updated 1 Oct 2026
Q55. Which of the following have true value if universe of discourse consist of all integers:
A. ∃n (2n = 3n)
B. ∀n (n² ≥ n)
C. ∀n (2n > n)
D. ∃n (n² = 2)
E. ∀x∀y ∃z (xy = z)
Choose the correct answer from the options given below:
  1. B, C and E only
  2. A, B and E only
  3. A, B, C and D only
  4. B, C, D and E only
Answer & explanation →
Q57. How many solution does the equation x + y + z = 11 have, where x, y, z are non-negative integers?
  1. 33
  2. 66
  3. 68
  4. 78
Answer & explanation →
Q80. Match the LIST-I with LIST-II.
Each of the following relations is defined on set {1, 2, 3, 4}. Match the relation types.
LIST-I (Relation)LIST-II (Relation type)
A. {(2,2), (2,3), (2,4), (3,2), (3,3), (3,4)}I. Antisymmetric
B. {(2,4), (4,2)}II. Only transitive
C. {(1,2), (2,3), (3,4)}III. Only symmetric
D. {(1,3), (1,4), (2,3), (2,4), (3,1), (3,4)}IV. neither symmetric, nor transitive
Choose the correct answer from the options given below:
  1. A-II, B-III, C-I, D-IV
  2. A-II, B-III, C-IV, D-I
  3. A-IV, B-III, C-I, D-II
  4. A-I, B-III, C-IV, D-II
Answer & explanation →
Q84. How many edges are there in a graph with 10 vertices each of degree six?
  1. 60
  2. 15
  3. 20
  4. 30
Answer & explanation →
Q85. Arrange the following in ascending order on the basis of number of distinct prime numbers in their prime factorization.
A. 729
B. 1001
C. 1111
D. 420
Choose the correct answer from the options given below:
  1. A, C, B, D
  2. D, A, B, C
  3. A, B, C, D
  4. D, A, C, B
Answer & explanation →
Q89. Which of the following additional properties is supposed to be satisfied by a group (G, *) to be an abelian group?
  1. Commutative
  2. Identity
  3. Inverse
  4. Associativity
Answer & explanation →
Q90. Suppose P(·) is used for power set and ∅ is the usual notation of empty set. Arrange the following on the basis of their cardinality in non-decreasing order:
A. P({a, b, {a,b}})
B. P({∅, a, {a}, {{a}}})
C. P(P(∅))
D. P(P({a}))
E. P({{a,b}, c})
Choose the correct answer from the options given below:
  1. C, D, A, B, E
  2. D, C, E, A, B
  3. C, D, E, A, B
  4. D, C, B, A, E
Answer & explanation →
Q98. Match the LIST-I with LIST-II. Match the equivalent propositions in List-I and List-II
LIST-ILIST-II
A. P→(Q→P)I. (P∨Q)∧¬(P∧Q)
B. P→(Q∨R)II. (P∨R)→Q
C. (P→Q)∧(R→Q)III. (P→Q)∨(P→R)
D. ¬(P⇔Q)IV. ¬P→(P→Q)
Choose the correct answer from the options given below:
  1. A-IV, B-II, C-III, D-I
  2. A-IV, B-III, C-II, D-I
  3. A-I, B-II, C-III, D-IV
  4. A-I, B-III, C-II, D-IV
Answer & explanation →
Q102. Match the LIST-I with LIST-II.
LIST-ILIST-II
A. Commutative lawI. P∧(Q∨R) = (P∧Q)∨(P∧R)
B. Distributive lawII. P∧(P∨Q) = P
C. Demorgan lawIII. P∧Q = Q∧P
D. Adsorption lawIV. ¬(P∨Q) = ¬P∧¬Q
Choose the correct answer from the options given below:
  1. A-III, B-IV, C-II, D-I
  2. A-II, B-I, C-IV, D-III
  3. A-III, B-I, C-IV, D-II
  4. A-IV, B-II, C-III, D-I
Answer & explanation →
Q103. Let and

be subgroups of group . Which of the following is False?

  1. H1.H2 = {h1*h2 : h1 ∈ H1 and h2 ∈ H2} is a subgroup.
  2. H1.H2 = {h1*h2 : h1 ∈ H1 and h2 ∈ H2} is a normal subgroup given that H1 and H2 are normal subgroups.
  3. is a subgroup.
  4. is a subgroup.
Answer & explanation →
Q105. A tree is :
A. a circuitless connected graph
B. a connected graph of 'n' vertices with (n − 1) edges
C. a circuitless graph of 'n' vertices with (n − 1) edges
D. a minimally connected graph
Choose the correct answer from the options given below :
  1. A, B and C only
  2. B, C and D only
  3. A, B, C and D
  4. A and B only
Answer & explanation →
Q106. Consider the following List-I and List-II in context of graph & model.
LIST-ILIST-II
A. Planar GraphI. Probabilistic Model
B. Bipartite GraphII. Deterministic Model
C. PERTIII. 4 - Colorable
D. CPM (Critical Path Method)IV. 2 - Colorable
Choose the correct answer from the options given below:
  1. A-III, B-IV, C-I, D-II
  2. A-IV, B-III, C-I, D-II
  3. A-II, B-IV, C-I, D-III
  4. A-III, B-IV, C-II, D-I
Answer & explanation →
Q112. The number of vertices of odd degree in any graph of 'n' vertices with 'e' edges is :
  1. odd
  2. even
  3. (n − e)
  4. prime
Answer & explanation →
Q116. Let R = {(1, 2), (3, 4), (2, 2)} and S = {(4, 2), (2, 5), (3, 1), (1, 3)} be two relations. The composite relation R∘S of R and S is :
  1. (4, 2), (3, 2), (2, 5)
  2. (1, 5), (3, 2), (2, 5)
  3. (1, 3), (3, 1), (2, 5)
  4. (2, 5), (3, 1), (2, 3), (3, 3)
Answer & explanation →
Q120. Out of 32 people, 30 save paper and 14 people save plastic bottles. What is the total number of people who save both paper and plastic bottles? Assume all people save either paper or plastic bottles or both paper and plastic bottles.
  1. 12
  2. 14
  3. 16
  4. 18
Answer & explanation →
Q122. Consider a linear program {max cᵀx | Ax ≤ b}. Which of the following statements is true?
  1. the dual program is {min bᵀy | Aᵀy ≤ c, y ≥ 0}
  2. the dual program is {min bᵀy | Aᵀy ≥ c, y ≥ 0}
  3. the dual program is {min bᵀy | Aᵀy = c, y ≥ 0}
  4. the dual program is {max bᵀY | AᵀY = c}
Answer & explanation →

Answer key

  1. 55 – B
  2. 57 – D
  3. 80 – A
  4. 84 – D
  5. 85 – A
  6. 89 – A
  7. 90 – C
  8. 98 – B
  9. 102 – C
  10. 103 – A
  11. 105 – C
  12. 106 – A
  13. 112 – B
  14. 116 – B
  15. 120 – A
  16. 122 – C