4 smart ways to solve ‘Coding-Decoding’ questions

4 smart ways to solve 'Coding-Decoding' questions

As all are aware that a bank entrance exam tests your aptitude. Quantitative Aptitude, Reasoning Ability, English Language and General Awareness are the key areas tested in a bank entrance exam.

‘Coding-Decoding’ is a part of the Reasoning Ability section. You can either score brilliantly or waste a lot of time with no satisfactory output. The more prepared you are, the better is your score.

This article will take you through ‘Coding-Decoding’ concepts and smart ways to solve questions based on ‘Coding-Decoding’. Let’s first understand what coding and decoding is? What types of questions are asked from this topic?

What is ‘Coding-Decoding’?

  • Coding is a way of transmitting data between the sender and the receiver in an encrypted manner i.e. without any other person knowing about it.
  • Before transmission, the data is encoded and when it is received, it is decoded in order to obtain the original data.
  • This prevents the data from getting corrupt and leaked.

After knowing what coding and decoding are, let us further read about what type of questions are asked in bank & SSC exams.

The relevance of ‘Coding-Decoding’ in Reasoning section?

  • ‘Coding and Decoding’ carries significant weightage in various banking & SSC exams, not only this these questions are asked in various other recruitment exams. The concept and approach remain the same, only the level of difficulty varies.
  • In SSC exams, the level of difficulty in easy to moderate while in bank exams, the level of difficulty is difficult.
  • There are 5-7 questions based on ‘Coding and Decoding’ in bank/SSC exams.
  • Classification of ‘Coding and Decoding’ questions is as follows:
    • Letter Coding
    • Substitution
    • Mixed Letter Coding
  • Mixed Number Coding

Furthermore, let’s go on a fruitful journey to know smart ways to solve ‘Coding-Decoding’ questions.

Smart approach to solving ‘Coding-Decoding’ questions

  • Observe alphabets or numbers given in the question
  • Try to find the pattern or sequence it follows. They could be in ascending or descending order, arranged in an alternate fashion and other ways as well.
  • Figure out the rule followed by the given arrangement of alphabets/numbers/words

Basic points you need to remember before solving any question of this topic.

  • Alphabets’ positions (A=1, B=2,……,Y=25, Z=26)
  • Opposite position of alphabet (A=26, B=25,……, Z=1)
  • Opposite of each alphabet (A is opposite to Z, B is opposite to Y and so on)
  1. Letter coding:

In this type of questions, the alphabets in a word are replaced by other alphabets according to a specific rule.

For instance: In a certain code, “PARKING” is written as “RYTIKLI”. How will FLOWERS be written in that code?

Explanation: Find out the pattern by comparing the 1st letter of PARKING with the 1st letter of RYTIKLI.

We observe that P is converted to R. R is two positions after P.

Now A is converted to Y. So, we can conclude that A is two positions before Y.

So, PARKING is coded as +2 and -2 alphabets in an alternate manner.

Using the same logic, we can decode flowers

F – (+2) – H

L – (-2) – J, as so on

The correct answer is ‘HJQUHPQ’.


In such questions, names/words are substituted with different names/words. We have to carefully trace the substitution to arrive at the correct answer.

For instance: If ‘Parrot’ is known as ‘Peacock’, ‘Peacock’ is known as ‘Swallow’, ‘Swallow’ is known as ‘Pigeon’, ‘Pigeon’ is known as ‘Sparrow’, what would be the name of the national bird?

Explanation: We know ‘peacock’ is the national bird. But in the given question, ‘Peacock’ is coded as ‘Swallow’. So ‘Swallow’ is the correct answer.


In this type of question, three-four phrases are given in coded language and the code for a particular word is asked.

To solve such questions, any two phrases with a common word are picked up. The common code word will refer to that word. Proceeding in a similar manner, all possible combinations of two phrases are selected and a common code is picked up.

Let us solve IDBI PO 2012 actual question.

In a certain code language,

  1. ‘new banking system’means ‘ss tp na’
  2. ‘officer in uniform’means ‘or mu at’
  3. ‘new bank officer’means ‘or bk na’
  4. ‘systems in bank’means ‘bk at ss’
  • What is the code for ‘in’?

Explanation: In statements (2) and (4), the common code word is ‘in’ and the common code is ‘at’.

  • What does the code ‘bk’ standS for?

Explanation: In statements (3) and (4), the common code word is ‘bk’ and the common word for that is ‘bank’.


In this type of questions, numbers are given corresponding to phrases. Following the same rule as in the above case, we can easily find out the answer. Selecting two phrases at a time, you have to find out the number code for each word and then arrive at the correct answer.

Now let us solve a RBI grade B question.

In a certain code,

‘467’ means ‘leaves are green’,

‘485’ means ‘green is good’

‘639’ means ‘they are paying’.

What is the number code for ‘leaves’?

Explanation: In statements 1 and 3, the common word is ‘green’ and the common number is ‘4’. So, ‘4’ is for ‘green’. Now, in statements 1 and 2, ‘are’ is common and ‘6’is common. So, ‘6’ stands for ‘are’.

In statement 1, only ‘leaves’ and ‘7’ are remaining, therefore ‘leaves’ corresponds to ‘7’.

Now, since must have developed a good command over Coding- Decoding questions. To streamline your practice, enroll for CL’s Reasoning Speed Tests. You can also take FREE tests on our blog.