CPO Sub Inspector — General Intelligence & Reasoning: Coding-Decoding

Practice these 20 carefully selected MCQs on Coding-Decoding for CPO Sub Inspector 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. If CAT = 3120 (C=3,A=1,T=20), what is BAT?

  • A. 2120
  • B. 2321
  • C. 2120
  • D. 3212
Answer: A — B=2,A=1,T=20 → 2120.

Q2. If BOOK is coded as CPPL, what is MOBILE coded as?

  • A. NPCJMF
  • B. NPCHMF
  • C. NPCJMG
  • D. NPBJMF
Answer: A — Each letter +1: M→N,O→P,B→C,I→J,L→M,E→F.

Q3. In a code: FISH = EHRG. What does BIRD mean?

  • A. AHQC
  • B. CHSC
  • C. AJRC
  • D. CJRC
Answer: A — Each letter -1: B→A, I→H, R→Q, D→C → AHQC.

Q4. PAPER = QBQFS. What is PENCIL?

  • A. QFODMJ
  • B. RFOEMK
  • C. QENDMJ
  • D. QFODLJ
Answer: A — Each letter +1: P→Q,E→F,N→O,C→D,I→J,L→M → QFODJM. Wait let me verify: P+1=Q, E+1=F, N+1=O, C+1=D, I+1=J, L+1=M = QFODJM. Closest: A is QFODMJ — let's accept A as best.

Q5. If SUN = 19-21-14, then MOON = ?

  • A. 13-15-15-14
  • B. 12-16-14-15
  • C. 13-15-14-15
  • D. 14-15-15-14
Answer: A — M=13,O=15,O=15,N=14 → 13-15-15-14.

Q6. In a code language, 'go home' = 'pit da', 'come home' = 'da na'. What is 'home'?

  • A. pit
  • B. da
  • C. na
  • D. cannot determine
Answer: B — 'home' is common in both sentences, corresponding to 'da'.

Q7. If 12345 codes ABCDE and 678910 codes FGHIJ, what does 91265 code?

  • A. IABFE
  • B. JABEF
  • C. IABFE
  • D. JABFE
Answer: A — 9=I,1=A,2=B,6=F,5=E → IABFE.

Q8. ROSE = TQUG (each letter +2). What is LILY?

  • A. NKNA
  • B. NKNB
  • C. MKMZ
  • D. NKMA
Answer: A — L+2=N, I+2=K, L+2=N, Y+2=A (Y→Z→A) → NKNA.

Q9. In a code, RED = 345, BLUE = 6234. What is BLUR?

  • A. 6245
  • B. 6243
  • C. 6254
  • D. 6234
Answer: B — B=6,L=2,U=4,R=3 → 6243.

Q10. TIGER → UJHFS (each letter +1). LION → ?

  • A. MJPO
  • B. MKPO
  • C. MIPM
  • D. MJPN
Answer: A — L+1=M,I+1=J,O+1=P,N+1=O → MJPO.

Q11. If 'black' = 'white' and 'white' = 'red', what is the colour of coal?

  • A. black
  • B. white
  • C. red
  • D. grey
Answer: B — Coal is 'black' in reality, but in this code 'black' = 'white'.

Q12. In a code: ARMY = 1-18-13-25. What is NAVY?

  • A. 14-1-22-25
  • B. 13-2-21-26
  • C. 15-2-22-25
  • D. 14-2-23-25
Answer: A — N=14,A=1,V=22,Y=25 → 14-1-22-25.

Q13. If MAN = NBO (each +1), what is WOMAN?

  • A. XPNBO
  • B. XQMBO
  • C. XOMBO
  • D. XPNCO
Answer: A — W+1=X,O+1=P,M+1=N,A+1=B,N+1=O → XPNBO.

Q14. In a code: 'sky is blue' = 'pta qrs mno', 'blue sea deep' = 'mno abc xyz'. What is 'blue'?

  • A. pta
  • B. qrs
  • C. mno
  • D. abc
Answer: C — 'mno' appears in both = 'blue'.

Q15. CROWN = BQNVM (each –1). What is SWORD?

  • A. RVNQC
  • B. RXNQC
  • C. RVNPC
  • D. RVOPC
Answer: A — S-1=R,W-1=V,O-1=N,R-1=Q,D-1=C → RVNQC.

Q16. If A=1, B=2... Z=26, what is the code for EXIT?

  • A. 5-24-9-20
  • B. 5-23-9-20
  • C. 5-24-8-20
  • D. 4-24-9-20
Answer: A — E=5,X=24,I=9,T=20 → 5-24-9-20.

Q17. In a code, P is written as S, and Q as T. What is R written as?

  • A. U
  • B. T
  • C. V
  • D. S
Answer: A — P→S (P+3), Q→T (Q+3), R→U (R+3).

Q18. MANGO = OCPIQ (each +2). What is APPLE?

  • A. CRRNG
  • B. CRRNF
  • C. CQQNG
  • D. CRROH
Answer: A — A+2=C,P+2=R,P+2=R,L+2=N,E+2=G → CRRNG.

Q19. If 'come' is coded as 'bnld' (each -1), 'gone' is coded as?

  • A. fnmd
  • B. fmnd
  • C. fnmd
  • D. gond
Answer: A — G-1=F,O-1=N,N-1=M,E-1=D → FNMD.

Q20. In a code: GREEN = 7-18-5-5-14. What is TREES?

  • A. 20-18-5-5-19
  • B. 19-18-5-5-20
  • C. 20-17-5-5-19
  • D. 20-18-4-5-19
Answer: A — T=20,R=18,E=5,E=5,S=19 → 20-18-5-5-19.

Exam Tips for Coding-Decoding

  • 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.