Practice Questions for Coding & Decoding | Logical Reasoning (LR) and Data Interpretation (DI) - CAT PDF Download

Q1: If in a certain language, PAPER is written as OZODQ. Which word would be written as RZKD?
(a) SEAL
(b) SALE
(c) SELL
(d) SKIP
Ans: (b)
Explanation: Each letter in the code is the previous letter in the alphabet (A → Z, B → A, C → B, ...). To decode RZKD, shift each letter one step forward: R → S, Z → A, K → L, D → E, giving SALE. Hence option (b).
Q2: If in a certain language, TRIANGLE is written as SSHBMHKF. In the same language, COUNTRY is written as:
(a) BPVOSSX
(b) DNVMUQZ
(c) BPTOSSX
(d) DNVNVQ
Ans: (c)
Explanation: The code alternates a shift of -1 and +1 for successive letters: 1st letter -1, 2nd letter +1, 3rd -1, 4th +1, and so on. Applying this to COUNTRY: C(-1)→B, O(+1)→P, U(-1)→T, N(+1)→O, T(-1)→S, R(+1)→S, Y(-1)→X. This gives BPTOSSX, option (c).
Q3: In a certain code language, ANGLE is coded as IJKMN and STRIKE is coded as OPQRSN. How can TRIANGLE be coded in the same language?
(a) PQRQJJMN
(b) PQMNROJJ
(c) POMNROJJ
(d) PQRIJKMN
Ans: (d) 
Explanation: Determine letter-to-letter mapping from the given examples. From ANGLE → I J K M N we get A→I, N→J, G→K, L→M, E→N. From STRIKE → O P Q R S N we get S→O, T→P, R→Q, I→R, K→S, E→N (consistent for E). Applying these mappings to TRIANGLE (T R I A N G L E) gives T→P, R→Q, I→R, A→I, N→J, G→K, L→M, E→N. Thus TRIANGLE → P Q R I J K M N, which is option (d).
Q4: If in a certain code language, TEACHER is coded as klmnolp. How can EARTH be coded in the same language?
(a) lmpok
(b) lmpko
(c) lmkop
(d) lmokp
Ans: (b)
Explanation: Map letters from TEACHER → k l m n o l p, so T→k, E→l, A→m, C→n, H→o, R→p. Apply to EARTH: E→l, A→m, R→p, T→k, H→o. So EARTH → l m p k o, option (b).
Q5: If BITER is coded as KLMNO in a certain language. How can TRIBE be coded in the same language
(a) MOLNK
(b) MOLKN
(c) MOKLN
(d) MOKNL
Ans: (b)
Explanation: From BITER → K L M N O we map B→K, I→L, T→M, E→N, R→O. Apply to TRIBE: T→M, R→O, I→L, B→K, E→N giving MOLKN, option (b).
Q6: If F = 6, CAT = 24, then WORD =?
(a) 59
(b) 60
(c) 61
(d) 62
Ans: (b)
Sol:
F = 6 because F is the 6th letter of the alphabet.
C = 3, A = 1, T = 20 → CAT = 3 + 1 + 20 = 24.
W = 23, O = 15, R = 18, D = 4 → WORD = 23 + 15 + 18 + 4 = 60.
Therefore WORD = 60, option (b).
Q7: If EDUCATION is coded as 2F5D1V34P, then how can EQUAL be coded?
(a) 2R15M
(b) 2RM15
(c) 2R51M
(d) 2R5M1
Ans: (c)
Explanation: Vowels are replaced by their vowel-order numbers: A→1, E→2, I→3, O→4, U→5. Consonants are replaced by the next consonant in the alphabet (skip vowels): C→D, D→F, N→P, T→V, Q→R, L→M, etc. From EDUCATION we confirm E→2, D→F, U→5, C→D, A→1, T→V, I→3, O→4, N→P. Now EQUAL: E→2, Q→R, U→5, A→1, L→M → 2 R 5 1 M. Written as 2R51M, option (c).
Q8: In a certain code language, 'pen pencil' is written as '$%' and 'eraser sharpener' is written as '@#' and 'pencil eraser' is written as '$@'. Then, what is the code for 'pen'?
(a) #
(b) $
(c) @
(d) %
Ans: (d)
Explanation: From 'pencil eraser' = $@ we get pencil → $ and eraser → @. From 'pen pencil' = $% and pencil → $ so pen must be %, option (d).
Q9: In a certain code language,‘commit also make policy’ is written as � !y6 #t6 @o4,‘policy craze anger mobile’ is written as !y6 @r5 � #e5,‘allow mild course prize’ is written as !e5 � #e6 @w5,‘craze manner pump artist’ is written as %r6 #e5 !p4 @t6
Then, what does #e6 #e5 @o4 stand for?
(a) artist mild craze
(b) also make course
(c) craze also course
(d) commit course mobile
Ans: (c)
Explanation: 

• From ‘allow mild course prize’ = !e5 � #e6 @w5,
  → #e6 = course
• From ‘policy craze anger mobile’ and ‘craze manner pump artist’,
  the common word craze corresponds to
  → #e5 = craze
• From ‘commit also make policy’ = � !y6 #t6 @o4,
  → @o4 = also

Therefore,
#e6 #e5 @o4 = course craze also,
which matches option (c): craze also course.
Q10: If '+' stands for '-' , '-' stands for 'x', 'x' stands for '÷'and '÷'stands for '+' .Then, what is the value of 56x7÷13-11+15-8÷2-7?
(a) 30
(b) 60
(c) 95
(d) 45
Ans: (d)
Explanation: Replace operators as given: x → ÷, ÷ → +, - → ×, + → -. The expression becomes:
56 ÷ 7 + 13 × 11 - 15 × 8 + 2 × 7
Evaluate multiplications/divisions first:
56 ÷ 7 = 8
13 × 11 = 143
15 × 8 = 120
2 × 7 = 14
Now compute: 8 + 143 - 120 + 14 = 45.
Hence the value is 45, option (d).
Q11: If U + V means U is the brother of V, W − X means W is the father of X, X × Y means X is the sister of Y, Y ÷ Z means Z is the mother of Y, then which of the following means that N is the mother of O?
(a) L + M ÷ O
(b) L − M × O ÷ P
(c) M + L × O ÷ N
(d) N × M + L ÷ O
Ans: (c)
Explanation: From the symbol definitions: Y ÷ Z means Z is the mother of Y.
In option (c), the segment O ÷ N appears.
According to the rule, O ÷ N means N is the mother of O.
The remaining symbols describe other family relations but do not affect the required conclusion.
Hence, the correct answer is option (c).
Q12: If 'A' denotes "divided by", 'B' denotes "added to", 'X' denotes "subtracted from", 'R' denotes "multiplied by", then 18 R 12 A 4 X 8 B 6 =?
(a) 52
(b) 102
(c) 45
(d) 32
Ans: (a)
Explanation: Translate symbols: R → ×, A → ÷, X → -, B → +. So the expression is 18 × 12 ÷ 4 - 8 + 6.
Evaluate multiplication/division first: 18 × 12 = 216; 216 ÷ 4 = 54.
Then 54 - 8 + 6 = 46 -? Wait compute: 54 - 8 = 46; 46 + 6 = 52.
Hence the result is 52, option (a).

Direction (13 - 15): Read the following information carefully and answer these questions:
In a certain coding system,

• '816321' means 'the big lion scared the rat';
• '64851' means 'the scared rat ran away';
• '7621' means 'the rat was big';
• '341' means 'the lion ran'

Q13: What is the code for 'the lion was scared'?
(a) 8763
(b) 8731
(c) 8453
(d) 8463
Ans: (b)
Explanation: Compare the given coded lines to find which digit corresponds to which word. From 341 = 'the lion ran' we get the set {3,4,1} → {the, lion, ran}. From 7621 = 'the rat was big' and 64851 = 'the scared rat ran away' match common digits to common words; after matching all overlaps we obtain the mapping: 1 → the, 2 → big, 3 → lion, 4 → ran, 6 → rat, 7 → was, 8 → scared. Using these assignments, 'the lion was scared' corresponds to the digit sequence for (the, lion, was, scared) → 1 3 7 8. In the option list this arrangement appears as 8731 (as the coded format used in the question set), so choose (b).
Q14: What is the code for 'big'?
(a) 1
(b) 3
(c) 4
(d) 2
Ans: (d)
Explanation: From the overlapping codes, big corresponds to digit 2. For example, 7621 represents 'the rat was big'; with known mappings for the other words, 2 must be 'big'. Hence option (d).
Q15: What is the code for 'rat'?
(a) 5
(b) 6
(c) 4
(d) 3
Ans: (b)
Explanation: From the comparisons (for example 816321 and 64851), the digit common to phrases containing 'rat' is 6. Thus 6 codes 'rat', option (b).

Directions (16 - 19): Study the following information to answer the given questions:
Study the following information to answer the given questions:
In a certain code language ' hard  of perusing  MBBS' is written as 'cl sa nk jo', 'Nepal  diminishes  in education' is written as 'ha fa rs da', 'MBBS education   of Nepal' is written as 'sa rs cl da' and 'hard MBBS  in Nepal' is written as 'cl fa jo da'.
Q16: What is the code for 'MBBS education' in the given code language? 
(a) cl fa 
(b) cl rs
(c) da fa 
(d) rs da 
Ans: (b)
Explanation: From 'MBBS education of Nepal' = sa rs cl da and 'hard MBBS in Nepal' = cl fa jo da, the common codes for MBBS and education are sa and rs or cl and rs; comparing all lines shows MBBS → cl and education → rs. Therefore MBBS education → cl rs, option (b).
Q17: What does the code 'jo' stand for in the given code language?
(a) hard
(b) in 
(c) Nepal
(d) education
Ans: (a)
Explanation: Compare sentences: 'hard of perusing MBBS' = cl sa nk jo and 'hard MBBS in Nepal' = cl fa jo da. The common code in both that must represent 'hard' is jo. Hence jo → hard, option (a).
Q18: What is the code for 'Nepal' in the given code language?
(a) rs 
(b) da 
(c) fa 
(d) Can't be determined 
Ans: (b)
Explanation: From 'MBBS education of Nepal' = sa rs cl da and 'hard MBBS in Nepal' = cl fa jo da, the common code for Nepal is da. Hence Nepal → da, option (b).
Q19: 'nk fa da' is the code for which of the following?
(a) Education of Nepal
(b) Diminished in Nepal
(c) Perusing in Nepal
(d) Can't be determined
Ans: (c)
Explanation: From mappings: nk → perusing, fa → in, da → Nepal. Therefore 'nk fa da' decodes to 'perusing in Nepal', option (c).
Q20: If + means ÷, × means -, ÷ means × and - means+, than 16 + 12 × 8 ÷ 6 - 8 =?
(a) -12
(b) -20/3
(c) 20/3
(d) -116/3
Ans: (d)
Explanation: Replace operators: + → ÷, × → -, ÷ → ×, - → +. So the expression becomes:
16 ÷ 12 - 8 × 6 + 8
Apply precedence (multiplication/division first): 16 ÷ 12 = 4/3; 8 × 6 = 48.
Now compute: (4/3) - 48 + 8 = (4/3) - 40 = (4 - 120)/3 = -116/3.
Hence the value is -116/3, option (d).