Shortcuts in Reasoning for Competitive Exams – Coding-Decoding
In this segment of commonsense reasoning, secret messages or words have to be decoded. They are coded as per a definite pattern/ rule which should be identified first. Then the same is applied to decode another coded word.
TYPE-1 CODING BY LETTER SHIFTING
Coding in forward sequence
EXAMPLE 1. If ‘GOOD’ is coded as ‘HPPE’, then how will you code ‘BOLD’ ?
Solution . Here,every letter of the word ‘GOOD’ shifts one place in forward alphabetical sequence.
Similarly, every letter in the word ‘BOLD’ will move one place in forward alphabetical sequence as given below:
Code for ‘BOLD’ will be ‘CPME’.
Coding in backward sequence.
EXAMPLE 2. If‘NAME’is coded as
‘MZLD’, then how will code ‘SAME’?
Solution . Here, every letter of the word ‘MZLD’ moves one place in backward alphabet sequence. Let us see:
Similarly, every letter of the word ‘SAME’ will move one place in backward alphabet sequence. Let us see :
Code for ‘SAME’ will be ‘RZLD’.
Coding based on skipped sequence.
EXAMPLE 3. If the word ‘FACT’ is
coded as ‘IDFVV’; then how will you code ‘DEEP’ ?
Solution . Here, every letter of the word shifts three place in forward alphabetical order.
Similarly, ‘DEEP’ can be coded. Let us see :
Code for ‘DEEP’ will be ‘GHHS’.
- Observe alphabets given in the code carefully .
- Find the sequence it follows whether it is ascending/descending .
- Detect the rule in which the . alphabets follow.
- Fill the appropriate letter in the ‘L blank given.
TYPE-2 : CODING BY SUBSTITUTION
In this coding, some words are replaced by some substituted words and on the basis of substituted word the code is derived.
EXAMPLE 4. If’ `cages’ are called ‘rockets’, ‘rockets’ are called ‘traps’, ‘traps’ are called ‘planets’, ‘planets’ are called ‘aeroplanes’, ‘aeroplanes’ are called ‘cycles’ are cycles’ are called ‘cars’, what is Earth
(a) Cycles (b) Rockets (c) Planet (d) Aeroplanes (e) Cars
Solution . Earth is a planet and here planets are called aeroplanes. So, earth will be called aeroplanes.
TYPE-3 : CODING BY REVERSING LETTERS
In this coding, all letters of a word has been reversed.
EXAMPLE 5. If‘TEMPERATURE’is coded as ‘ERUTAREPMET’, then how will you code ‘EDUCATION’following the same scheme.
Solution . Here, the word ‘TEMPERATURE’ has been reversed. Hence, the code for ‘EDUCATION’will be ‘NOITACUDE’.
TYPE 4 : CODING IN FICTION LANGUAGE
In some cases of coding-decoding, fictions language is used to code some words. In such questions, the codes for a group of words is given. In such types of problems, codes for each word can be found by eliminating the common words.
EXAMPLE 6. In a certain code language ‘over and above’ is written as ‘da pa ta’ and ‘old and beautifiil’ is written as ‘Sa na pa’. How is ‘over’ written in that code language?
Clearly, ‘and’ is common in both and a common code is ‘Pa’.
.’. Code for ‘and’ must be ‘Pa’. Code for ‘over’ = ‘da’ or ‘ta’.
Code for above = ‘da’ or ‘ta’.
Gode for old = ‘Sa’ or ‘na’
Code for beautiful = ‘Sa’ or ‘na’
We can’t certainly say what will be exact code for ‘over’. But it is sure that code for ‘over’ must be either ‘da’ or ‘ta’.
- Firstly, write the words and their codes as given in the question in straight line with an arrow in middle.
- Now, find the common words and their corresponding codes.
- Encircle each pair with the same shape.
- Finally, we have each word and its corresponding code.
TYPE-5 : CODING BASED ON NUMBERS
When numerical values are given to words.
EXAMPLE 7. If in a certain language A is coded as 1, B is coded as 2. C is coded as 3 and so on, then find the code for AEECD .
Solution . As given the letters are coded as below:
Code for AEECD= 15534
- First you have to observe the number code.
- Now, notice the position of number.
- Search the common pattern.
When alphabetical code value are given for numbers.
EXAMPLE 8 . In a certain code 3 is coded as ‘R’, 4 is coded as ‘D’, 5 is coded as ‘N’, 6 is coded as ‘P’, then find the code for ‘53446’.
Solution . As per the given condition
Code for 53446 = NRDDP.
TYPE-6 : MATHEMATICAL OPERATIONS WITH THE POSITION NUMBERS OF LETTERS
EXAMPLE 9. In a certain code, if ‘TALE’ is written as 38, then how will you code ‘CAME’ using the same coding scheme?
Solution . Look at the numbered alphabet and write down the number corresponding to the letters of the word‘TALE’.
The fact that the code for ‘TALE’ is 38, gives you a clue that the code is probably obtained by performing an arithmatical operations of the numbers of each other. Let us see :
20+1+12 + 5 = 38 Thus, the code for ‘CAME’ is
Code for‘CAME’= 22
If the letters in the code look the same as in the original text, it will be a scramble type coding.
If more than one codes are given then likely the required code can be drived from the question itself and you will not need to solve it mathematically.
If the code for a word is a one digit number then likely the position of the letters are added and the digits are summed up until the one digit number is arrived at.
TYPE-7 : MATRIX CODING
In this type of questions two matrices are given. In each matrix there are 25 cells and these cells contain two classes of alphabets. The columns and rows of matrix I are numbered from 0 to 4 and that of matrix II from 5 to 9. A letter from these matrices can be represented first by its row number and next by its column number. For example. ‘A’ Can be represented by 32 or 43.
Directions: In each of the following questions find out the correct set of number pairs for the given word from the two matrices given above.