3rd Class Mental Ability Coding-Decoding Coding-Decoding

Coding-Decoding

OBJECTIVE

•   To transmit an information from one place to other using some codes so as to reach to other person safely.
•    To judge a child's ability to decipher the rule that codes a particular word and number.

Introduction

A Code is a 'system of signals'. Coding is a method of transmitting a message between the sender and the receiver without a third person knowing it.

Before transmitting, the data is encoded and at receiver side encoded data is decoded in order to obtain original data by determining common key in encoded data.

Types of Coding-Decoding

1. Letter Coding

2. Number Coding

3. Substitution Coding

Type I: Letter Coding

In this type, the real alphabets are replaced by certain other alphabets according to a specific rule to form its code. Students are required to detect the common rule and answer the questions accordingly.

Case 1: Direct Letter Coding

Example - 1

In a certain code, RAN is written as SBO and BAT is CBU, then how will RAT be written in that code?

(a) SAU                         (b) RBT       

(c) SBU                         (d) UBS

Ans. (c)

Explanation:

By direct code method, we get

R\[\to \]S, A\[\to \]B, T\[\to \]U

So, RAT will be written as SBU.

Case 2: To form the code for another word (CODING)

Example - 2

In a certain language, SUN is coded as TVO, then how is FUN coded in that code?

(a) FVO                         (b) GVO      

(c) NUF                         (d) OVG

Ans. (b)

As,   

Similarly,  

So, FUN would be coded as GVO

Type II: Number Coding

In these questions, either numerical code values are assigned to a word or alphabetical code letters are assigned to the numbers. Students are required to analyse the code as per the question.

Example - 3

If in a certain code, FOUR is written as 3256 and MARE is written as 4167, how is MORE written in that code?

(a) 3416                        (b) 4267        

(c) 4326                         (d) 7624

Ans. (b)

Explanation:

The alphabets are coded as shown:

So, In MORE,

M\[\to \]4, O\[\to \]2, R\[\to \]6, E\[\to \]7

Thus, the code for MORE is 4267.

Type III: Substitution Coding

In these types of questions, letter of words are substituted for either a new letter or a numeric.

Example - 4

If 'pen' is 'table', 'table' is 'fan', 'fan' is 'chair' and 'chair' is 'roof, then which of the following will a person sit?

(a) Fan                          (b) Chair       

(c) Roof                         (d) Table

Ans. (c)

Explanation:

A person will sit on the 'chair' and 'chair' is called 'roof?.

So, the person will sit on the 'roof'.