Coding - Decoding | General Test Preparation for CUET

What is Coding-Decoding?

Coding is a process used to encrypt a word, a number in a particular code or pattern based on some set of rules. Decoding is a process to decrypt the pattern into its original form from the given codes.

• A Code is a signal. Coding has always been used to transmit messages in such a way that they are not ordinarily understood unless these are decoded.
• These messages can only be understood by the receiver if he has the ‘code key’ to decipher it.
• Thus, the “Coding-Decoding” test is given to judge the candidate’s ability to decipher the ‘rule applied in coding’.
• The coding is generally based on alphabets and some times numerals are also used to code the messages.

There are a few tips which will help in solving the coding decoding questions:

• Read the question carefully and write down key code.
• Try to decode the coding given in the question. Candidates must note that similar type of decoding can be applied to various questions.
• Try to simplify the code by using the elimination method and remove the unwanted values.
• Solve more and more practise questions to understand the concept even better and to score more in questions based on this topic easily. For coding-decoding questions, candidates can visit the linked article and enhance their Government exam preparation.

Let’s revise these tips and tricks with some examples: 

Example 1:  In a certain code language:

• ‘given  time  simple  plan’ was written as ‘@E4  &N4  %N5  #E6’
• ‘tired  solution  plant  great’ was written as ‘#N8  @D5  %T5  &T5’
• ‘sick  point  good  turn’ was written as ‘#K4  �  @N4  &T5’
• ‘garden  sister  phone  team’ was written as ‘&E5  #R6  %N6  @M4’

What will be the code for ‘translate’?

(a) #E8

(b) @E9

(c) @E8

(d) #T9

Ans: Correct Answer is Option (b)

• Step I: First count the alphabets in the word ‘translate’ which is 9, put 9 at the end.
• Step II: Put the last alphabet of ‘translate’ before the digit 9 so now the code is E9 till now.
• Step III: At the last step ‘t’ is coded for ‘@’(the first letter of each word is coded by a specific symbol like here ‘t’ is coded for ‘@’. We can find the first coded symbol by looking at the other given words. The answer will be - @E9

Here in this example there are some points to be kept in mind: 

Points to Remember:

• In this question it is seen that all the steps have all 4 words starting with alphabet G, T, S and P, with that the codes start with symbols @, %, & and #.
• So now just the match between the first alphabet and the particular symbol is to be found.
• The next thing to observe is that the codes are ending with digits. This represents the total alphabets used in each word.
• Analysing the middle code in the word reflects the last alphabet of their respective word.
  

Types of Coding-Decoding
Though all the methods of coding cannot be identified but still the major formats of coding are as under:

• Type 1: Coding based on alphabet.
• Type 2: Coding based on symbols and numbers.
• Type 3: Coding based on renaming.
• Type 4: Coding based on group of words.
• Type 5: Miscellaneous.

Type 1: Coding Based on Alphabet

• Reversal of Alphabets
  The alphabets of the word are reversed in such a way that the last letter is the code of the first letter. It is the easy format of the coding and it is the first thing to be looked when we look at coding.

Example 2: In a certain code language BREAKDOWN is written as NWODKAERB. How will TRIANGLES be written in that code language?
(a) AIRTGNSEL
(b) SELGWTRIA
(c) AIRTNSELG
(d) SELGNAIRT

Ans: Correct Answer is Option (d)
The order of letters has been reversed in the code.
Following the coding given above, TRIANGLES will be Coded as SELGNAIRT.

• Opposite Letters
  The second type of coding is by ‘use of opposite letters’. We can understand this type from the rule of 27, which informs us how to find out the opposite letters of the alphabet. Knowing the position value of each alphabet and using the second rule of 27, we can easily find out if the word is coded in ‘opposite letters’. Here A will be coded as Z. Therefore, B will be coded as Y and C will be coded as X.

Example 3: In a certain code ORDER is written as LIWVI. How is SUBSTITUTION written in that code?
(a) HFYHGRGFGRLM
(b) HFHYGRGRLM
(c) HFYHGRGRML
(d) HFYHGRHGGQLM             

Ans: Correct Answer is Option (a)
A perusal of the word ORDER and its coded word LIWVI and knowledge of the second rule of 27 shows that L is opposite letter of O, I is opposite of R, W is opposite of R and so on. It means that the coded word contains all the opposite letters. Keeping this in view, we know that SUBSTITUTION will be coded as HFYHGRGFGRLM.

• Preceding / Following
  In this type of questions either preceding or following letter stands as the code letter for each of the letters of the given word.
  Example:
  
  

Example 4: In a certain code language, ‘TEMPORARY’ is written as ‘SFLQOQBQZ. How would ‘WONDERFUL’ be written in the same code?
(a) VPMEFQGTM              
(b) VPMEESGTM              
(c) XPMEEQGTM
(d)  None of these

Ans: Correct Answer is Option (d)
     
Similarly,

We observe that letters are alternatively moved one place forward and one place backwards and the letter in the middle of the given word is not changed. Based on this observation, we coded the word ‘WONDERFUL’ as ‘VPMEEQGTM’.

• Jumbling of Letters
  In this type of coding, the letters of the given word are moved in a particular way and for the purpose of decoding, the same format is required to be followed. In jumbling also a series has to be there.  

Example 5: In a certain code language AUTHORITY is written as YTUROHTIA. How will DESIGNATE be written in that code language?
(a) ESENGATDI  
(b) ESEGNITAD  
(c) ESENGITAD  
(d) ESNEIGTDA

Ans: Correct Answer is Option (c)
In the coded form the first and the last (ninth) letters have been interchanged so as the second and third, the fourth and the sixth and the seventh and the eighth letters while middle letters (i.e. fifth) is left intact. Thus,

Similarly,

• Adding Up Place Value
  It is some time observed that the given word is coded in numeric form. Generally, the place values of the letters used in the word are added up and the resultant sum is the coded form of the given word. If the word CAT is coded as 24 because the place value of all the letters are added up.

Example 6: If MADRAS is coded as 56, how is CALCUTTA coded in that language?
(a) 80
(b) 81
(c) 82
(d) 76   

Ans: Correct Answer is Option (b)
The place value of all the letters is added up.

Similarly, Calcutta can be coded in the same way as:

Directions: Given two words & to find Code for Third

Example 7. If the word ‘NUMBER’ is coded as ‘EPRSAY’ and ‘SQUARE’ is coded as ‘NGPVYA’ then how do we code ‘MEMBER’. 
(a) RARSYA      
(b) RRASYA      
(c) RARSAY      
(d) SARSAY

Ans: Correct Answer is Option (c)

• When we observe the coded word and the corresponding, code it is observed that the coding is neither in the form of opposite letters; nor correspond place value in the alphabet. 
• The only thing common between the two coded words are the letters U and E and these letters are coded as P and A respectively in both the given words. Their placement in the code corresponds to their position in the coded words. 

Based on this information, we draw the table as shown below and find the code for each letter:

If we observe from the table above table, M is coded as R, E is coded as A, B is coded as S. So the answer is RARSAY.            

Type 2: Coding Based on Symbols and Numbers

• In the symbol coding, we use the symbols like “!@#$%^&*()_”, to represent words or letters. These codes are then used to determine a code for the words that are written down. 

Numbers coding involves two types of cases:

1. When numerical code values are assigned to words.
   Example: If D = 4 and COVER = 63, then BASIS = ?

   Clearly, in the given code, A = 1, B = 2, C = 3, ….. so that
   COVER = 3 + 15 + 22 + 5 + 18 = 63
   ∴ BASIS = 2 + 1 + 19 + 9 + 19 = 50.

2. When alphabetical code values are assigned to the numbers.
   Example:  In a certain code, ‘SPRING’ is written as ‘#2%@4=’ and ‘GONE’ is written as ‘=74(c). How would SIGN be written in the same code?
   (a) #@ = 4  
   (b) 2@ = 4            
   (c) #@ = 4            
   (d) #% = 4

Ans: Correct Answer is Option (c)

Type 3: Coding Based on Renaming

• In this type of questions, certain words are assigned different names and you are required to ascertain the code for a particular word.

Example 8: If ‘green’ is called ‘white’, ‘white’ is called ‘yellow’, ‘yellow’ is called ‘blue’, ‘blue’ is called ‘pink’ and ‘pink’ is called ‘black’, then what is the colour of milk?
(a) Green
(b) Blue
(c) Pink
(d) Yellow                           

Ans: Correct Answer is Option (d)

The colour of the milk is white. But the code of white is yellow, so the answer is yellow.

• In this type of questions, a group of words or a sentence as a whole is coded and on the basis of common words you are required to ascertain the code for each word.

Example 9: In a certain code: ‘ing ping sing’  means ‘how are you’ , ‘sing ring ding’ means ‘what about you’ and ‘ding fing ching’ means ‘what to do’ ,then how is ‘do’ written in this code language? 
(a) ing  
(b) fing  
(c) ching
(d) data inadequate                           

Ans: Correct Answer is Option (d)

• In the first and second sentence, ‘you’ is common while in the coded statement, the common word is ‘sing’. It means that sing is the code for you. Similarly, in the second and third sentence, the common word is ‘what’ and ‘ding’ respectively. 
• From it, we can conclude that the coding for ‘what’ is ‘ding’. But for the ‘do’ we cannot assign the code because it can be coded either as’ fing’ or ‘ching’. Our answer to the question here should be ‘data inadequate’ or option number (4). Code for do is ‘fing’ or ‘ching’.

Example 10: Study the following information carefully and answer the questions given below:
The digits from 0 to 9 are coded as shown below with the exceptions that follow:

Exceptions:

• If number begins and ends with an odd digit (non-zero), then both the first and last digits are to be coded as $.
• If a number begins and ends with an even digit (including zero), then both the first and last digits are to be coded as #.

Q.1. What will be the code for 314926?                
(a) MPBDHA
(b) MPBTND
(c) MPBTNA
(d) $PBTN$      

Ans: Correct Answer is Option (b)

Q.2. ‘RATHIM’ represents which of the following numbers?
(a) 095873
(b) 059673
(c) 059871
(d) 059873          

Ans: Correct Answer is Option (d)

Q.3. What will be the code for 4521736?
(a) BANPIMD
(b) BANPIRD
(c) #ANPIM#
(d) #BAMPI#  

Ans: Correct Answer is Option (c)