Basic Concept Of CODING-DECODING For Banking/SSC/Railway

In this chapter, we are going to learn how to solve problems related to this topic. Firstly, we will understand what coding-decoding means.

It refers to the process of finding the pattern (or rules that transform one set of characters) into another. The main goal in coding-decoding questions is to decode a message or code based on the rule that applies to the relationship between the given elements.

There are different types of Coding-Decoding:

1. Letter Coding

2. Coding in Fictitious Languages

3. Coding by Analogy

4. Coding by Substitution

5. Coding by Shifting Words

6. Coding Based on Conditions

7. Mathematical Operation-Based Coding

Now we are going to understand the above topics one by one.

1. Letter Coding

(i) Coding by Shifting Letters

In this type of coding-decoding, letters are shifted by increasing or decreasing numbers.

Example 1: In a certain code language, the word LION is coded as KHNM. How will the word WATCH be written in that language?

(a) VSZGB (b) VZSBG (c) VZSCG (d) VZSAG (e) VZBSG

Solution (b):

Each letter is shifted one position backward in the alphabet.

L → K (−1)

I → H (−1)

O → N (−1)

N → M (−1)

Similarly,

W → V (−1)

A → Z (−1)

T → S (−1)

C → B (−1)

H → G (−1)

Therefore, WATCH → VZSBG.

Answer: (b) VZSBG

Note: Numerical Order of the Alphabet

For coding-decoding questions, you must know the numerical order of the alphabet from A to Z.

(ii) Coding by Rearranging Letters

In this type of coding, the letters of words are rearranged according to a particular pattern.

Example 2: In a certain code language, the word PENCIL is written as NEPLCI. How will the word LAPSED be written in that language?

(a) PALDES (b) PALDSE (c) PLADSE (d) LPASDE (e) S LPADE

Solution (b):

The letters of PENCIL are rearranged according to the following positions:

P E N C I L → N E P L C I

Original positions: 1 2 3 4 5 6

Rearranged positions: 3 2 1 6 4 5

Therefore,

L A P S E D → P A L D S E

Answer: (b) PALDSE

2. Coding in Fictitious Languages

In this type of coding, words are written in an imaginary or coded language.

Let’s see an example.

Example 3: Coding-Decoding

In a certain code, “tik la pe” means “my name is”; “pe ft ml” means “my fig fruit” and “la fe de” means “pen cap name”. What is the code for “is”?

(a) ft (b) ml (c) tik (d) tik or fe (e) None of these

Solution (c):

3. Coding by Analogy

In this type of coding, we can see three types of coding:

1. Coding by shifting letters

2. Digit coding

3. Symbol coding

(i) Coding by Shifting Letters

Example 4: In a certain code language, FEAR is written as HCCP and MAN is written as OYP. How is BAND written in that code?

(a) DPYF (b) DYFP (c) CYFP (d) DYPB (e) None of these

Solution (d):

FEAR → HCCP

• F + 2 = H

• E − 2 = C

• A + 2 = C

• R − 2 = P

Similarly,

MAN → OYP

• M + 2 = O

• A − 2 = Y

• N + 2 = P

Therefore,

BAND → DYPB

• B + 2 = D

• A − 2 = Y

• N + 2 = P

• D − 2 = B

Answer: (d) DYPB

(ii) Digit Coding

Example 5: In a certain code, FOAM is written as 6425 and BONE is written as 3471. How is MOAN written in that code?

(a) 5426 (b) 5427 (c) 4527 (d) 5429 (e) None of these

Solution (b):

From the given words, we obtain the following letter-to-digit mapping:

Similarly,

M O A N → 5 4 2 7

Therefore, MOAN = 5427.

Answer: (b) 5427

(iii) Symbol Coding

In this type of coding, letters are coded using both digits and symbols.

Example 6: In a certain code, FATHER is written as $%85#@ and STREAM is written as 48@#%2. How is HATERS written in that code?

(a) 5%8##4 (b) 5%8#@4 (c) %58#@4 (d) 5%8@#4 (e) None of these

Solution (b):

From the given words, we obtain the following mapping:

Similarly,

H A T E R S → 5 % 8 # @ 4

Therefore, HATERS = 5%8#@4.

Answer: (b) 5%8#@4

4. Coding by Substitution

In this type of coding, one word or object is represented by another word or object according to a given rule.

Example 7: White means black, black means red, red means blue, blue means yellow and yellow means grey. Then which of the following represents the colour of a clear sky?

(a) Yellow (b) Red (c) Blue (d) Grey (e) None of these

Solution (a):

The actual colour of a clear sky is blue.

According to the given code, blue means yellow.

Hence, the coded answer is Yellow.

Answer: (a) Yellow

5. Coding by Shifting Words

In this type of coding, words in a sentence are rearranged according to a particular sequence.

Example 8: If the sentence “The monk who sold his ferrari” is written as “who sold the his ferrari monk” in a certain code, then how will “Anyone can achieve everything in life” be written in that code?

Solution:

Original sentence:

The monk who sold his ferrari

Assign numbers to the words:

After coding:

who sold the his ferrari monk

Similarly, for the sentence:

Anyone can achieve everything in life

After coding, the rearranged sequence is:

achieve everything anyone in life can

6. Coding Based on Conditions

Directions (Questions 9–11): Digits in the numbers given in each of the following questions are to be coded based on the codes and conditions given below.

Conditions

(i) If both the first and the last digits of a number are odd, they should be coded as @.

(ii) If both the first and the last digits of a number are even, they should be coded as Z.

Example 9

3086175

Solution:

Condition (i) is applied.

The first and last digits are 3 and 5, respectively. Both are odd, so they are coded as @.

The remaining digits are coded normally.

Therefore, 3086175 → @BQVTR@

Example 10

534678

Solution:

No condition is applied because the first digit is odd and the last digit is even.

Therefore, 534678 → AKMVRQ

Example 11

258764

Solution:

Condition (ii) is applied.

The first and last digits are 2 and 4, respectively. Both are even, so they are coded as Z.

The remaining digits are coded normally.

Therefore, 258764 → ZAQRVZ

7. Mathematical Operation-Based Coding

In this type of coding, certain letters are assigned numerical values, and mathematical operations are performed using those values.

Example 12

If the alphabets are assigned values such as A = 8, B = 2, M = 4, Z = 3 and C = 5, find the sum of the values of the letters in ABMZC.

Solution:

Therefore,

8 + 2 + 4 + 3 + 5 = 22

Answer: 22

Note

Alphabets and their numerical or positional values play an important role in reasoning topics such as coding-decoding, machine input and alphabet series.

You should memorise these values to solve questions faster and more accurately.

Tips and Tricks: Reverse Alphabet and Numerical Values

To solve coding-decoding questions quickly, learn the reverse alphabet sequence and its numerical values.

 

 

Practice Qestion for Banking/SSC/Railway

1.

In a certain code language, “April” is coded as “lipra”. “August” is coded as “tsuuga”. What is the code for the month “December”?

(a) rebecedm (b) rmeebecd (c) rebmeced (d) rebmeecd (e) Can’t be determined

2.

In a certain code, “TRAIN” is coded as “OQBHU” and “WHEEL” is coded as “MGFDX”, then what will be the code for the word “GREEN”?

(a) ODFQH (b) XFPSJ (c) SPFXK (d) PFSXL (e) None of these

3.

In a certain code, “CONCEDE” is coded as “HIUHMG M” and “DAWDRY” is coded as “GYJGVK”, then what will be the code for the word “AWONY”?

(a) YJG NK (b) YJIUK (c) YNMKI (d) YJIOG (e) None of these

4.

If “SALES” is coded as “19@12%19” in the same way “LEAD” is coded as “12%@4”, then what will be the code of “CASET”?

(a) @1%19% (b) 3%19@20 (c) 31@19%20 (d) 3@19%20 (e) None of these

5.

If MODERN is written as OQFCPL and DELETE is written as FGNCRC in a certain way, then how is SEARCH written as?

(a) UGCPBF (b) UGCPAF (c) UHEQAE (d) USDPFF (e) None of these

6.

If “RIGHT” is coded as “IRTSG” and in the same way “UNITY” is coded as “FMRGB”, then how is “SCRIPT” coded in the given coded pattern?

(a) HBIRKG (b) HBSJKG (c) HXIRKG (d) HXIJQG (e) None of the above

7.

In a certain code, “GREEN” is coded as “OFFSH” and “BROWN” is coded as “OXFPS”, then what will be the code for the word “ROUND”?

(a) EPSFX (b) XFPSO (c) EOVPS (d) EPFSX (e) None of these