Coding – Decoding Shortcut Tricks for RRB and Other Competitive Exams

           There are different types of Coding and Decoding questions are there, before going into details lets first understand what is meant by coding and decoding. 

Coding : A particular code or pattern is used to express a word in English language to express it as a different word. The coded word itself does not make any sense unless we know the code, i.e., unless we know the pattern or code that has been followed. 

Decoding : Decoding refers to the process of arriving at the equivalent English word from the code word given. Hence, we can look at two broad categories of questions in Coding – Decoding.

In the 1st category of questions, a particular code is given and on the basis of this given code, we have to find out how another word (in English Language) can be coded. The correct code for the given word has to be selected from the answer choices on the basis of the code given in the question. 

Ex : In certain code if the word “VIRTUAL” is coded as “UHQSTZK”, then in this code, how is the word “PAINFUL” coded? 

By observation, we can find that in coding “VIRTUAL” as “UHQSTZK”, each letter in the given word has been replaced by the letter that comes immediately before it in the English alphabet. Using this code, if we now have to code “PAINFUL”, we need to replace each letter of the word with the letter that comes before it in the English alphabet. Thus the code will be “OZHMETK”. 

Note : Here, it can be seen form the example, we treat the English alphabet in a circular fashion. i.e., the letter that comes after Z is A. Similarly, the letter that comes before A is Z.

In the second category of questions, a particular code is given and on the basis of this given code, we have to find out the equivalent word in English language for a word given coded form.

The correct word (in English Language) for the given coded word has to be selected from the answer choices on the basis of the code given in the question.

Example : In a particular Code, if the word :SYSTEM” is coded as “UAUVGO”, then in teh same code, what does “HCUJKQP” stand for?

Sol : Here, we can observe that each letter in the given word is replaced by the second letter that comes after it in the English alphabet to give us the word in coded form. Hence, to know what “HCUJKOP”, we should replace each letter by a letter which second letter before it in the English alphabet. This gives us the word “FASHION”. The first step to be taken in solving questions in coding – decoding is to crack the code. To do this, it will be helpful to understand the broad types of codes that are used.

Of course, the number of codes that can be created and used are infinite but one can always keep the commonly used codes in mind. Secondly, practice will make a student much more comfortable and conversant with these types of questions.

Use the letter that comes one or any fixed number of places before it in the alphabet. Use a letter as many places from the end of the alphabet as the original letter is from the beginning of the alphabet.

Each vowel may be replaced by the next vowel that comes in the alphabet and each consonant by another consonant following certain pattern with reference to the consonant under consideration. Use one code for all the letters in even places in the given word and a different code for letters n the odd places in the given word to give a new word.

The same letters in the given word may be used in a cyclic or in some other order to give the coded word. Some numerical values can be attributed to the letters of the word based on the letter positions in the alphabet. Combination of two or more of the above ways of coding.

Basic shortcut techniques of Coding – Decoding section of Reasoning. Today we shall discuss some example problems of Coding and Decoding with detailed explanations.

Approach : The letters of the given word are written in a jumbled order to give us the word in the coded form. We need to find out the manner in which they have been jumbled. If you keenly observe the given words, the first letter of the word D has been used as the 3rd letter in the code. So, for the word PICTURE, the first letter P will have to be the third letter in the code. This eliminates choices (1) and (5), Then, the second letter I is used as the third from the last and that is not happening in choice (3). So, we now have choice (2) and (4). 

Since there are two As in the given word, let us leave aside A for the time being and look at some of the other letters. If we take the last letter M, it comes as the fourth letter in the code. SO, E in the word PICTURE should come as the fourth letter in the code. This leaves us only choice (2). So the correct answer is option (2). 

Note : Here, suppose even this has not given us a unique choice, we would then look at the remaining letters too.

Approach : Each letter in the given word “CODING” is replaced by the letter that immediately follows it in the English alphabet. Hence, the correct choice is option (1)

Approach : If we replace each letter of the word “ASHTRAY” by a letter which is three letters to the right of it in the alphabet, then we get “DVKWUDB“. So, to find out the word whose code is “UDQFLG“, we replace each letter in the code by a letter which comes three places behind in the alphabet. We then get “RANCID”as the word. Option (5).

Approach :The first letter is shifted by one alphabet forward, the second by one alphabet backward, the third by one forward and so on… So, the word “PRANESH” will be coded as “QQBMFRI“ which is option (3).

Approach : The first half of the word has the letters being moved back by one letter in the alphabet and the second half of the word has the letters being moved forward by one letter in the alphabet.  So, option (2).

Approach : An easy way to do these sort of problems is to Just remember the place values of the alphabets so that it will be easier for you to solve these type of problems.

According to above link, ALPHABET can be written as

A — > 1 (Odd Number) so we have to assign value 2

L –> 12 (Even Number) so we have to assign value 1

P –> 16  (Even Number) so we have to assign value 1

H —> 8 (Even Number) so we have to assign value 1

A — > 1 (Odd Number) so we have to assign value 2

B–> 2  (Even Number) so we have to assign value 1

E–> 5  (Odd Number) so we have to assign value 2

T–> 20  (Even Number) so we have to assign value 1

So the answer is 21112121. Which is option (1).

Approach : According to place values, the given word PAPERS can be written as

P –> 16 (multiple of 2) so we can write 2

A—> 1 (non multiple of 2) so we can write 1

P —> 16 (multiple of 2) so we can write 2

E —> 5 (non multiple of 2) so we can write 1

R—> 18 (multiple of 2) so we can write 2.

So the code will be 21212. Which is option (5).

Approach : In these type of questions, we cannot get the code for all the letters of the alphabet but we can get the code for the letters of the word “MANGO” which is of interest to us. Take one by one of these letters of the word “MANGO” and look for the code of that specific letter from the words for which the code is already given to us.

Here, in this case, when we observe that R, A and N are the first three letters of both the given words in the same order and the code for both words have 1, 2 and 3 in that order at the beginning. Because of lack of any additional information, we then conclude that the code for R is 1, A is 2 and N is 3 and that the letters given in the code are in the same order as the letters given in the word. Thus, we can make out that the code for MANGO is 82347 on the basis of the code different letters of the word can be given. Choice (3).