Types of Coding and Decoding Questions for CAT: Variations, Tips, Tricks, and Questions

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Types of Coding and Decoding Questions for CAT: This is a major section featured in nearly all banking exams, such as IBPS PO, SBI PO, IBPS Clerk, RRB Officer Scale I, SBI Clerk, and others. Moreover, competitive examinations usually have a separate portion for Coding-Decoding Reasoning questions. Additionally, these questions evaluate a candidate’s ability to identify and apply patterns or rules used in decoding information. To work on these questions effectively, candidates must be familiar with the positions of letters in the alphabet from both left to right and right to left. In this blog, students will get to know what is coding and decoding all about, their types, tricks and much more.

Also Read: CAT Archives

What is Coding and Decoding?

Coding-Decoding affects encrypting or decrypting words, letters, or sentences according to specific rules or patterns. In addition, this technique guarantees that only the intended recipient can understand the message. Different Coding and Decoding methods challenge logical reasoning and improve concentration skills. When a message is crafted to hide its true meaning from everyone except the intended recipient, it is known as Coding. On the other hand, Decoding is the process of interpreting this hidden message to reveal its original meaning, understandable only by the designated person.

Also Read: Coding Decoding Questions and Answers, Concepts, Types

Types of Coding and Decoding Questions for CAT?

By now, you are familiar with the types of coding and decoding questions for CAT. Let us explore the different categories of reasoning questions on coding-decoding individually below: 

Letter-to-Letter Coding

Letter-to-letter coding is like a hidden language where regular letters are replaced with other letters following a specific rule. Suppose you and a friend want to write messages others can not understand. You decide to shift each letter forward by one spot in the alphabet. So, A becomes B, B becomes C, and so on.

Letter to Number Coding

Letter-to-number coding is like creating a confidential language where letters are replaced with numbers. Let’s Imagine you have a decoder ring, but rather than letters turning into different letters, they turn into numbers!

Substitutional Coding

Substitution coding is usually used in tests and puzzles to see if you can crack the code and figure out the hidden message. It is like a brain teaser to test your thinking skills!

LSN Coding

LSN Coding is a type of puzzle found in some competitive exams, particularly those for banking jobs in India. It tests your ability to decode a secret code.

Conditional Coding

Let’s suppose you’re giving instructions to a friend. Conditional coding is like telling your friend what to do depending on a certain situation. In coding, we use words such as “if,” “else,” and “then” to tell the computer these conditions and actions.

 Clock Coding

Clock coding can be done in a few different ways, but the basic idea is always the same: use code to show the current time. There are two main types of clocks.

  • Digital clock: This shows the time as you see on your phone or oven, with numbers for hours, minutes, and sometimes seconds.
  • Analogue clock: This is the kind with hands that spin around a circle to show the time.

Binary Coding

Suppose a language computers understand, is made up of just two words: “on” and “off.” That is kind of what binary code is! It is a way of using just 0s and 1s to denote information like numbers, letters, or instructions.

Read More: Basic Coding Decoding CAT Sample Questions for Practise 2024: Download Free PDF

Tips and Tricks to Resolve Coding Decoding Questions in Reasoning

Candidates can find various tips and tricks for solving coding and decoding reasoning questions below.

Tip 1: The EJOTY method is useful for quickly identifying nearby letters. Refer to the table below for details.


Tip 2: For efficient solving of Letter-to-Letter coding-decoding questions, start by examining if opposite letters are used in the code. Next, check if the positions of the letters have been swapped. Finally, look for any operations like addition or subtraction that might have been applied.

Tip 3: To quickly tackle letter-to-number coding and decoding questions, begin by verifying if the code uses the positional values of letters. Then, see if these positional values have been swapped. Also, consider if the letters’ positional values are based on a reversed alphabetical order. Lastly, determine if any operations such as addition, subtraction, or multiplication have been applied.

Source: Jagran Josh

Practise Different Types of Coding and Decoding Questions for CAT

Instruction: Solve the following questions mentioned below and then cross-check your answers.

Question 1: In a certain code language, “CAT” is written as “123” and “DOG” is written as “456”. How is “RAT” coded in this language?

Answer 1: This code seems to be a simple alphabetical shift. Each letter is replaced by the number 3 positions ahead of it in the alphabet. (C -> F = 3 positions)

Following the pattern:

  • R (18th letter) + 3 = V (21st letter) = 7
  • A (1st letter) + 3 = D (4th letter) = 4
  • T (20th letter) + 3 = W (23rd letter) = 9

Therefore, “RAT” is coded as “749”.

Question 2: If “HAKUNA MATATA” is coded as “23154 11241124”, how is “SECRET” coded?

Answer 2: This code assigns a unique two-digit number to each letter.

  • Look for repetitions in the coded message. “11” appears twice, likely representing the letter “E”.

Now, analyze the first word:

  • “HAKUNA” – “23” could be H, “15” could be A, “4” could be K, and so on.

Test your hypothesis with the repeated number:

  • If “11” is E, then the second “11” likely represents the second “E” in “SECRET”.

Following the pattern:

  • S (19th letter) -> Two-digit code starting with 1 (avoiding repetition with E’s code) -> 18
  • E (5th letter) -> We already know this is “11”
  • C (3rd letter) -> Two-digit code starting with 0 -> 03
  • R (18th letter) -> Same logic as S -> 17
  • E (5th letter) -> “11”
  • T (20th letter) -> Two-digit code starting with 1 -> 19

Therefore, “SECRET” is coded as “181103171119”.

Question 3: Decode the following series: 1, 4, 9, 16, 25.

Answer 3: The series represents the square of consecutive natural numbers, so the decoded series is 1, 2, 3, 4, 5.

Read other related blogs

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Reasoning Questions: Types, Sample Ques, WorksheetGeneral Intelligence and Reasoning Syllabus For SSC
Top 10 Coding Interview Questions With AnswersHow-To-Practice-Logical-Reasoning-For-CAT-Exam


Do you think coding-decoding is there in CAT?

Test Level 1: Coding Decoding for CAT 2024 is part of CAT preparation. The Test Level 1: Coding Decoding questions and answers have been prepared according to the CAT exam syllabus. The Test Level 1: Coding Decoding MCQs are made for the CAT 2024 Exam.

Do you think coding-decoding is tough?

Coding, Decoding, and Reasoning are some of the most complex topics in the Reasoning section.

Is the CAT score useful?

CAT is primarily conducted to shortlist candidates for admission to the 20 IIMs. However, other non-IIM colleges also consider CAT scores for MBA admissions. A good CAT score for a top B school typically falls within the range of 198 to 180.

This was all about the types of coding and decoding questions for CAT. For more informative blogs, check out our Management Exams Section, or you can learn more about us by visiting our  Indian exams page of Leverage Edu.

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