Junior Engineers: General Intelligence & Reasoning — Venn Diagrams Practice MCQs (2026)

Practise these 20 carefully crafted MCQs on Venn Diagrams designed for Junior Engineers 2026. Each question carries a detailed explanation to reinforce learning.

Q1. Set A={1,2,3,4}, B={3,4,5,6}. A∩B?

  • A) {1,2}
  • B) {3,4}
  • C) {1,2,3,4}
  • D) {5,6}
Answer: B) {3,4} — Intersection contains elements in both sets.

Q2. A∪B for A={a,b,c} and B={b,c,d}?

  • A) {a,b}
  • B) {b,c}
  • C) {a,b,c,d}
  • D) {c,d}
Answer: C) {a,b,c,d} — Union = all elements in either set.

Q3. In a class 40 like cricket, 30 like football, 20 like both. Like only cricket?

  • A) 20
  • B) 10
  • C) 30
  • D) 40
Answer: A) 20 — Only cricket=40-20=20.

Q4. Venn diagram: Total=100, A=45, B=30, A∩B=15. A∪B?

  • A) 60
  • B) 65
  • C) 60
  • D) 75
Answer: C) 60 — 45+30-15=60.

Q5. Neither A nor B = Total - A∪B. Total=80, A=50, B=40, A∩B=20. Neither?

  • A) 5
  • B) 10
  • C) 15
  • D) 20
Answer: B) 10 — A∪B=70; Neither=10.

Q6. Set A−B (A minus B) for A={1,2,3,4,5}, B={3,4,5,6,7}?

  • A) {1,2}
  • B) {3,4,5}
  • C) {6,7}
  • D) {1,2,3}
Answer: A) {1,2} — A−B = elements in A not in B.

Q7. In survey: 70 read paper, 50 read magazine, 30 read both. Read only magazine?

  • A) 20
  • B) 20
  • C) 30
  • D) 40
Answer: B) 20 — Only magazine=50-30=20.

Q8. If A⊂B (A is subset of B), then A∩B=?

  • A) A
  • B) B
  • C) ∅
  • D) A∪B
Answer: A) A — If A⊂B, every element of A is in B, so A∩B=A.

Q9. Survey: 100 people; tea=60, coffee=50, both=30. Neither?

  • A) 10
  • B) 15
  • C) 20
  • D) 25
Answer: C) 20 — Tea∪Coffee=80; Neither=20.

Q10. In three sets A, B, C — all three intersect. Elements only in A∩B (not C) shown by?

  • A) Centre
  • B) Crescent between A and B
  • C) Only A region
  • D) Only B region
Answer: B) Crescent between A and B — The lens-shaped area between A and B excluding C.

Q11. A={multiples of 3 <20}, B={multiples of 4 <20}. A∩B?

  • A) {3,4}
  • B) {12}
  • C) {6,12}
  • D) {4,8,12}
Answer: B) {12} — Multiples of 12 less than 20: {12}.

Q12. Symmetric difference A△B = (A∪B)−(A∩B). For A={1,2,3}, B={2,3,4}?

  • A) {2,3}
  • B) {1,4}
  • C) {1,2,3,4}
  • D) {1,4}
Answer: C) {1,2,3,4} — A△B = {1,4}.

Q13. In Venn diagram of 3 sets, maximum regions?

  • A) 4
  • B) 6
  • C) 8
  • D) 10
Answer: C) 8 — 3 sets divide plane into at most 8 regions.

Q14. Total students=200. Passed Maths=120, Science=100, both=60. Passed at least one?

  • A) 140
  • B) 150
  • C) 160
  • D) 180
Answer: C) 160 — 120+100-60=160.

Q15. If n(A)=20, n(B)=15, n(A∩B)=5, n(A∪B)?

  • A) 25
  • B) 30
  • C) 35
  • D) 40
Answer: B) 30 — 20+15-5=30.

Q16. In a group, 55% like A, 45% like B, 20% like both. Like only A?

  • A) 35%
  • B) 40%
  • C) 45%
  • D) 50%
Answer: A) 35% — 55-20=35%.

Q17. Complement of A in universal set U: if n(U)=50, n(A)=30, n(A')?

  • A) 15
  • B) 18
  • C) 20
  • D) 25
Answer: C) 20 — 50-30=20.

Q18. Set builder: {x:x is a vowel} = ?

  • A) {a,e,i,o,u}
  • B) {a,b,c}
  • C) {p,q,r}
  • D) {a,i,u}
Answer: A) {a,e,i,o,u} — Five vowels.

Q19. A has 3 members, B has 4. Max elements in A∪B?

  • A) 3
  • B) 4
  • C) 7
  • D) 12
Answer: C) 7 — All distinct: 3+4=7.

Q20. If A and B are disjoint, n(A∪B)?

  • A) n(A)×n(B)
  • B) n(A)+n(B)
  • C) n(A)-n(B)
  • D) n(A)
Answer: B) n(A)+n(B) — Disjoint means no intersection, so union = sum.