SSC CHSL Reasoning preparation tips: coding-decoding

In the following article, we will discuss about the coding-decoding concept including various tips & tricks to resolve various kinds of inquired problems.

Created On: Feb 6, 2018 17:32 IST
ssc reasoning preparation tips
ssc reasoning preparation tips

As it is known to all that SSC measures one’s ability on the basis of performance in Quantitative Aptitude, General Intelligence & Reasoning, General English and General knowledge. All of them carry equal weight & same regulations in terms of maximum marks and in negative marks in all phases of SSC CHSL exam. However, some sections are quite easy while others are cumbersome and time-consuming. In the same fashion, reasoning section is a blend of such questions, which ranges from the easier ones to the toughest ones. Reasoning section is all about testing one’s ability of questioning and thinking logically.

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Coding-Decoding is a topic that falls under the reasoning ability section. You can try it brilliantly or spare a plenty of time having no appropriate responses. To overcome this problem & for gaining high scores, candidates have to practice harder.

In the following article, we will discuss about the coding-decoding concept including various tips & tricks to resolve various kinds of inquired problems.

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SSC CHSL preparation tricks: Coding-Decoding

Before heading to coding-decoding tips & tricks, we will look upon a short introduction of this topic. What is coding-decoding and what are its types?

Coding-decoding is a method of transmitting data/information in encrypted form between the sender and the receiver without anybody’s consent. Prior to transmission, the data is encoded first and sent through a medium and at the receiving end, it is decoded accordingly in order to procure the original data. Hence, data/information is prevented from distortion and leakage.

Beyond this, coding-decoding carries a significant weightage in various competitive exams including SSC CHSL. The concept and approach for exams remains the same except the difficulty level of questions varies in Tier-1 & 2 exams. Out of this topic, candidate will find one question minimally in SSC CHSL Tier-1 exam. Coding-Decoding includes four types of questions out of which questions may be framed in reasoning section of SSC CHSL exam.

  1. Letter coding
  2. Substitution
  3. Mixed letter coding
  4. Mixed number coding

Now, Let us discuss about the methods to solve such questions-

  1. Read alphabets or numbers in the given question.
  2. Find the pattern or sequence in ascending, descending or alternate pattern
    1. Alphabet’ positions (A=1, B=2, C=3,……., Y=25, Z=26)
    2. Opposite position of alphabet (A=26, B=25,…………., B=2,A=1)

Letter coding

Under this category, the alphabets in the given word are replaced by other random alphabets following a specific rule.

E.g. In a certain code, TEACHING is to UFBDIJOH. How BOOKS will be encoded in this code?

The answer is: Each alphabet in the word is incremented by 1 in the standard sequence. Hence, the answer will be CPPLT.


Under this category, names/words/strings are substituted with different words/names/strings. Therefore, we have to trace the substitution carefully to arrive at the appropriate answer. Let us understand with an example-

E.g. If orange is called banana, banana is called soap, soap is called ink, ink is called motorcycle and motorcycle is called paper, which of the following is used for washing clothes?

The Answer is ink because soap is known as ink. Hence, ink is the right answer.

Mixed Letter Coding

In this type of coding and decoding, Three-four statements are stated in a coded language under a problem and the code for a specific word is asked. For handling such questions, pick a random number of two or more phrases, which will have some similarity and dissimilarity. The similarity will be equal to each other. Hence, you can find out the code for each relevant string.

E.g. In a certain code,

1. ‘pity dare name’ means ‘you are good’
2. ‘dare token pawn’ means ‘good and bad’
3. ‘time name token ’ means 'they are bad’
In that language, which word stands for 'they'?

Let us figure out the code and letter for each string-

In statement (1) & (2): ‘dare’& ‘good’ are common between them. Hence, dare==good;

Similarly, comparing the remaining statements, we will get: token== bad; name== are;

Hence, the correct answer will be ‘time’ for ‘they’ string.

Mixed Number Coding

In this type of encryption, the numbers are given in the format of letters or phrases or strings. By following the same rule mentioned above, you can figure out the correct answer. Let us understand this with an example-

E.g. In a certain code,

'$^&' means 'leaves are green';

'$*%' means 'green is good' and

'^#!' means 'they are playing'.

Which symbol stands for 'leaves' in that code?

In the above question, $ is common in first two statements. Hence, $ will correspond to ‘green’. Hence, we can deduce the relationship between other statements.

^’ stands for ‘are’;

Hence, the correct answer is ‘&’ from the very first statement.

For more tips and tricks related to SSC exam preparation, you can visit us at .

All the Best!

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