All Exams — General Intelligence & Reasoning: Series Completion

Practice these 20 carefully selected MCQs on Series Completion for All Exams 2026. Each question includes the correct answer and a clear explanation. Practising MCQs regularly is the best way to improve speed and accuracy.

Instructions

  • Attempt all questions without looking at answers first.
  • Time yourself: target 1 minute per question.
  • Review explanations for every wrong answer.

Q1. AB, BC, CD, DE, __?

  • A. EF
  • B. FF
  • C. FG
  • D. EE
Answer: A — Consecutive letter pairs shifting by 1.

Q2. Z, X, V, T, __?

  • A. R
  • B. S
  • C. Q
  • D. P
Answer: A — Every alternate letter backwards. T-2=R.

Q3. A, C, F, J, O, __?

  • A. U
  • B. T
  • C. V
  • D. W
Answer: A — Gaps: +2,+3,+4,+5,+6. O+6=U.

Q4. AZ, BY, CX, DW, __?

  • A. EV
  • B. FW
  • C. EU
  • D. EX
Answer: A — First letters A,B,C,D,E; second letters Z,Y,X,W,V.

Q5. 1A, 2B, 3C, 4D, __?

  • A. 5E
  • B. 4E
  • C. 6F
  • D. 5D
Answer: A — Number and letter both increment by 1.

Q6. AB, EF, IJ, MN, __?

  • A. QR
  • B. OP
  • C. PQ
  • D. RS
Answer: A — Gaps of 4 between pairs: AB,EF,IJ,MN,QR.

Q7. ACE, BDF, CEG, DFH, __?

  • A. EGI
  • B. FHI
  • C. EHJ
  • D. EGJ
Answer: A — Each trio shifts by 1: A+1=B,C+1=D,E+1=F... → EGI.

Q8. Z, Y, X, W, V, U, __?

  • A. T
  • B. S
  • C. R
  • D. Q
Answer: A — Alphabet backwards, one at a time.

Q9. ABA, BCB, CDC, DED, __?

  • A. EFE
  • B. EEF
  • C. FEF
  • D. EFF
Answer: A — Pattern ABA→BCB: outer letters move forward by 1, inner by 1.

Q10. 2Z, 4Y, 6X, 8W, __?

  • A. 10V
  • B. 10W
  • C. 9V
  • D. 10U
Answer: A — Numbers +2; letters -1. 10V.

Q11. A1, B4, C9, D16, __?

  • A. E25
  • B. F25
  • C. E20
  • D. D25
Answer: A — Letters A,B,C,D,E; numbers 1²,2²,3²,4²,5²=25.

Q12. PPQ, QQR, RRS, SST, __?

  • A. TTU
  • B. TUU
  • C. TTV
  • D. UTV
Answer: A — Each letter group: double first, single second; shift by 1.

Q13. M, N, P, S, W, __?

  • A. B
  • B. A
  • C. C
  • D. D
Answer: A — Gaps: 1,2,3,4,5. W+5=B (wrapping alphabet).

Q14. BC, FG, JK, NO, __?

  • A. RS
  • B. ST
  • C. QR
  • D. TU
Answer: A — Pairs with gap: BC(2-3), FG(6-7), JK(10-11), NO(14-15), RS(18-19).

Q15. A, BB, CCC, DDDD, __?

  • A. EEEEE
  • B. EEEEE
  • C. FFFF
  • D. DDDDD
Answer: A — Each letter repeats n times.

Q16. YXW, WVU, UTS, SRQ, __?

  • A. QPO
  • B. QOP
  • C. PQO
  • D. OPQ
Answer: A — Decreasing triples, skipping one each time.

Q17. a1b, c2d, e3f, g4h, __?

  • A. i5j
  • B. h5i
  • C. j5k
  • D. i4j
Answer: A — Consecutive letters and numbers incrementing.

Q18. ABD, CEG, FHK, ILP, __?

  • A. MQV
  • B. LPU
  • C. NPT
  • D. MOU
Answer: A — Differences in positions: +2,+3; +3,+4; +4,+5...

Q19. 1, 4, 9, 16, 25, __?

  • A. 36
  • B. 30
  • C. 32
  • D. 34
Answer: A — Perfect squares. 6²=36.

Q20. A, Z, B, Y, C, X, __?

  • A. D
  • B. W
  • C. DW
  • D. D,W
Answer: C — Alternating from start and end of alphabet: A,Z,B,Y,C,X,D,W. Next pair = D,W.

Exam Tips for Series Completion

  • Regular practice of 20+ questions daily builds speed and accuracy.
  • Review your mistakes — understanding why you got it wrong is crucial.
  • Attempt this topic in full mock tests under timed conditions.