CPO Sub Inspector: General Intelligence & Reasoning — Missing Numbers Practice MCQs (2026)

Practise these 20 carefully crafted MCQs on Missing Numbers designed for CPO Sub Inspector 2026. Each question carries a detailed explanation to reinforce learning.

Q1. 2, 4, 8, 16, ?

  • A) 24
  • B) 28
  • C) 32
  • D) 36
Answer: C) 32 — ×2 each time → 32.

Q2. 1, 4, 9, 16, ?

  • A) 20
  • B) 24
  • C) 25
  • D) 36
Answer: C) 25 — Perfect squares: 5²=25.

Q3. 3, 6, 11, 18, ?

  • A) 23
  • B) 25
  • C) 27
  • D) 29
Answer: C) 27 — Differences: 3,5,7,9 → next=27.

Q4. 2, 3, 5, 8, 13, ?

  • A) 18
  • B) 20
  • C) 21
  • D) 23
Answer: C) 21 — Fibonacci-like: 8+13=21.

Q5. 1, 2, 6, 24, ?

  • A) 96
  • B) 100
  • C) 120
  • D) 144
Answer: C) 120 — ×1,×3,×4,×5 → ×5? Actually factorials: 1!,2!,3!,4!,5!=120.

Q6. 10, 9, 7, 4, ?

  • A) 0
  • B) -1
  • C) 1
  • D) 2
Answer: A) 0 — Differences: -1,-2,-3,-4 → next=0.

Q7. 100, 50, 25, 12.5, ?

  • A) 5
  • B) 6
  • C) 6.25
  • D) 7
Answer: C) 6.25 — ÷2 each time → 6.25.

Q8. 7, 14, 28, 56, ?

  • A) 84
  • B) 100
  • C) 112
  • D) 128
Answer: C) 112 — ×2 → 112.

Q9. 1, 1, 2, 3, 5, 8, ?

  • A) 11
  • B) 12
  • C) 13
  • D) 16
Answer: C) 13 — Fibonacci: 5+8=13.

Q10. 2, 5, 10, 17, ?

  • A) 24
  • B) 25
  • C) 26
  • D) 28
Answer: C) 26 — Differences: 3,5,7,9 → next=26.

Q11. 144, 121, 100, 81, ?

  • A) 64
  • B) 72
  • C) 81
  • D) 90
Answer: C) 81 — Perfect squares descending: 12²,11²,10²,9²,8²=64.

Q12. 3, 7, 15, 31, ?

  • A) 45
  • B) 55
  • C) 63
  • D) 65
Answer: C) 63 — ×2+1: 3,7,15,31,63.

Q13. 0, 1, 1, 2, 3, 5, 8, ?

  • A) 12
  • B) 13
  • C) 14
  • D) 15
Answer: C) 14 — Fibonacci: 5+8=13.

Q14. 5, 10, 20, 40, ?

  • A) 60
  • B) 70
  • C) 80
  • D) 90
Answer: C) 80 — ×2 → 80.

Q15. 1, 8, 27, 64, ?

  • A) 100
  • B) 112
  • C) 125
  • D) 144
Answer: C) 125 — Cubes: 5³=125.

Q16. 45, 43, 40, 36, ?

  • A) 31
  • B) 32
  • C) 33
  • D) 34
Answer: A) 31 — Differences: -2,-3,-4,-5 → next=31.

Q17. 2, 6, 12, 20, 30, ?

  • A) 36
  • B) 40
  • C) 42
  • D) 48
Answer: C) 42 — n(n+1): 1×2=2,2×3=6,...6×7=42.

Q18. 4, 9, 16, 25, 36, ?

  • A) 45
  • B) 46
  • C) 48
  • D) 49
Answer: C) 48 — Perfect squares: 7²=49.

Q19. 1, 3, 6, 10, 15, ?

  • A) 18
  • B) 20
  • C) 21
  • D) 23
Answer: C) 21 — Triangular numbers: 6th=21.

Q20. 16, 8, 4, 2, ?

  • A) 0.5
  • B) 1
  • C) 1.5
  • D) 2
Answer: A) 0.5 — ÷2 each → 1.