
Mental Reasoning 6- Coding and Decoding practice Set Questions and Step-by-Step Solutions for Competitive Exams SSC, BSSC, Bank, Railways
Here’s a complete “Coding and Decoding Practice Set – designed exactly like SSC, Banking, Railways, BPSC, NDA exams. The set covers Easy → Moderate → High-level questions and includes all major types of coding and decoding.
Coding and Decoding Practice Set
Easy Level (1–10)
1. If CAT → DBU, then DOG → ?
Step: Each letter +1
C→D, A→B, T→U → D→E, O→P, G→H
Answer: EPH
Hindi: प्रत्येक अक्षर +1 → उत्तर = EPH
2. If TABLE → ELBAT, then CHAIR → ?
Step: Reverse letters
C H A I R → R I A H C
Answer: RIAHC
Hindi: अक्षरों को उल्टा → RIAHC
3. If A=1, B=2, … Z=26, then CAT → ?
C=3, A=1, T=20 → Answer: 3 1 20
Hindi: अक्षरों को क्रमांक से बदलें → 3 1 20
4. HELLO → IFMMP, then WORLD → ?
+1 shift each letter
W→X, O→P, R→S, L→M, D→E
Answer: XPSME
Hindi: प्रत्येक अक्षर +1 → उत्तर XPSME
5. CAT → XZG (A→Z, B→Y …), then DOG → ?
D→W, O→L, G→T → Answer: WLT
Hindi: अक्षरों का उल्टा क्रम → WLT
6. If CODE → FQGH, then GAME → ?
+3 shift each letter
G→J, A→D, M→P, E→H → Answer: JDPH
Hindi: प्रत्येक अक्षर +3 → उत्तर JDPH
7. If SUN → VXP, then MOON → ?
+3 shift each letter
M→P, O→R, O→R, N→Q → Answer: PRRQ
Hindi: प्रत्येक अक्षर +3 → PRRQ
8. DOG → 4 15 7 (A=1, B=2 …), then CAT → ?
C=3, A=1, T=20 → Answer: 3 1 20
Hindi: अक्षरों का क्रमांक → 3 1 20
9. If APPLE → BQQMF, then BANANA → ?
+1 shift each letter
B→C, A→B, N→O, A→B, N→O, A→B → Answer: CBOBOB
Hindi: प्रत्येक अक्षर +1 → उत्तर CBOBOB
10. SUN → RTO (Each letter –1), then STAR → ?
S→R, T→S, A→Z, R→Q → Answer: RSZQ
Hindi: प्रत्येक अक्षर –1 → RSZQ
Moderate Level (11–20)
11. If CAT → ZXC, DOG → ? (Reverse + shift –1)
C→B, A→Z, T→S → D→C, O→N, G→F → Answer: CNF
Hindi: उल्टा और –1 shift → CNF
12. If CLOCK → 3 12 15 3 11 14 (A=1…), then PEN → ?
P=16, E=5, N=14 → Answer: 16 5 14
Hindi: अक्षरों को क्रमांक → 16 5 14
13. If ROAD → ADOR (Reverse), then MILE → ?
MILE → ELIM → Answer: ELIM
Hindi: अक्षर उल्टा → ELIM
14. If TREE → VTTG (+2, +2, +2, +2), then LEAF → ?
L→N, E→G, A→C, F→H → Answer: NGCH
Hindi: प्रत्येक +2 → NGCH
15. If CAT → DBU (+1, +1, +1), then PAN → ?
P→Q, A→B, N→O → Answer: QBO
Hindi: प्रत्येक +1 → QBO
16. If BAG → #@&, then CAT → ? (# for A, @ for B …)
C→& , A→# , T→% → Answer: &#%
Hindi: प्रतीक कोडिंग → &#%
17. If SUN → RVM (–1, –1, –1), then STAR → ?
S→R, T→S, A→Z, R→Q → Answer: RSZQ
Hindi: –1 shift → RSZQ
18. If LOVE → 12 15 22 5, then HOPE → ?
H=8, O=15, P=16, E=5 → Answer: 8 15 16 5
Hindi: अक्षरों को क्रमांक → 8 15 16 5
19. If FISH → HGUK (+1, +1 …), then BIRD → ?
B→C, I→J, R→S, D→E → Answer: CJSE
Hindi: +1 shift → CJSE
20. If CODE → FQGH (+3 shift), then DATA → ?
D→G, A→D, T→W, A→D → Answer: GDWD
Hindi: +3 shift → GDWD
High Level (21–30)
21. If APPLE → LZZOV (A→L, B→Y pattern), then ORANGE → ?
O→B, R→I, A→L, N→M, G→T, E→V → Answer: BILMTV
Hindi: जटिल अक्षर पैटर्न → BILMTV
22. If CAT → DZG (+1, reverse middle?), then DOG → ?
D→E, O→N, G→H → Answer: ENH
Hindi: पैटर्न +1, middle reverse → ENH
23. If HELLO → OLLEH, then WORLD → ?
Reverse → DLROW → Answer: DLROW
Hindi: अक्षर उल्टा → DLROW
24. If MOON → PQQO (+1,+2,+1,+0), then STAR → ?
S→T(+1), T→V(+2), A→B(+1), R→R(+0) → Answer: TVBR
Hindi: क्रमिक shift → TVBR
25. If CAT → 3 1 20 (alphabet position), DOG → ?
D=4, O=15, G=7 → Answer: 4 15 7
Hindi: क्रमांक → 4 15 7
26. If SUN → RVM (–1, –1, –1), then MOON → ?
M→L, O→N, O→N, N→M → Answer: LNNM
Hindi: –1 shift → LNNM
27. If LOVE → GSVV (opposite alphabet), then HATE → ?
H→S, A→Z, T→G, E→V → Answer: SZGV
Hindi: अक्षर का उल्टा क्रम → SZGV
28. If TREE → VGGT (+2 shift), then LEAF → ?
L→N, E→G, A→C, F→H → Answer: NGCH
Hindi: +2 shift → NGCH
29. If CODE → #@&*, then DATA → ?
D→@, A→#, T→% , A→# → Answer: @#%#
Hindi: प्रतीक कोडिंग → @#%#
30. Odd one out coding:
DOG → 4 15 7
CAT → 3 1 20
BAT → 2 1 20
RAT → 18 1 20
Step: All numbers in sequence except DOG (15)
Answer: DOG
Hindi: DOG का कोड अलग → उत्तर = DOG
Summary:
- Easy (1–10): +1, –1, reverse, number substitution
- Moderate (11–20): Mixed shifts, symbols, numeric/alphabetic coding
- High (21–30): Complex patterns, mixed shifts, opposite letters, odd-one-out

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