Coding – Decoding Introduction

What is Coding and Decoding?

Coding is a method of transmitting a message between the sender and the receiver that no third person can understand it. The coding and decoding one’s ability of deciphering the rule and breaking the code to decipher the message will be tested to know.

In this chapter we cover 2 section of Coding and Decoding , first is Letter Coding, Number Coding and then Substitution. Now first we are mentioning few points to remember before doing this section.

1. Observe alphabets or numbers given in the code keenly.
2. Find the sequence it follows whether it is ascending or descending.
3. Detect the rule in which the alphabets/numbers/words follow.
4. Fill the appropriate letter/number/word in the blank given.

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Letter Coding

Alphabets in a word are replaced by other alphabets according to a specific rule to know its code. So the common rule should be detected first. Some examples are given below:

1) ‘ZYXW’ as coded as ‘ABCD’ then ‘STUV’ is coded as _______

Method: Z – A, Y– B, X – C, W – D

V – E, U – F, T – G, S – H

STUV = HGFE

Answer = HGFE

Rule = Front Alphabet= Back Alphabet.

 

2) ‘ bcd’ is coded as ‘def’ then ‘True’ is coded as __________

Method: b – d (+2)

c – e (+2)

d – f (+2)

+2 letters are considered in this code.

True – Vtwg

Answer = Vtwg.

 

3) ‘ Hyderabad ’ is coded as ‘Ixedszcze’ then ‘Chennai’ is coded as…………..

Method: H – I (+1)

Y – X (1–)

D – E (1+)

E – D (1-)

R – S (1+)

A – Z (1–)

B – C (1+)

A – Z (1– )

D – E (1+)

Here if we observe alternatively the letter increasing and one letter decreasing.

Chennai =dgfmozj

Answer = dgfmozj

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Number Coding

In this each alphabets or words are assigned to the numeric values we should observe the given letters and the assigned values and use the same rule to find the value to of given code.

Substitution: In this section an object names are substituted with different object names. We should carefully trace the substitution and answer given question.

1) ‘book’ is coded as ‘pencil’, ‘pencil’ is coded as ‘mirror’, ‘mirror is coded as ‘book’. Then what is useful to write on a paper?

Answer: Pencil is coded as mirror

Answer = mirror.

2) ‘man is coded as ‘woman’, woman is coded as ‘girl’, ‘girl’ is coded as ‘boy’, ‘boy’ is coded as ‘worker’ then 6 years female is known as?

Answer: 6 years female = girl, but ‘girl’ is coded as ‘boy’.

Answer = boy.

 

3) ‘Reds’ are ‘blues’, ‘blues’ are ‘whites’, ‘whites’ are ‘yellows’, ‘yellows’ are ‘oranges’, ‘oranges’ are ‘pinks’, then what is the colour of the sky?

Answer: Sky is blue, but blues are whites

Answer = white.

 

4)        If C E J Q is coded as X V Q J , then B D I P  will be coded as ………..

 

Sol: The first 13 letters of the alphabet are coded by the 13 letters of the alphabet in

reverse, i.e.

= A B C D E F G H I J K L M (first 13 letters)

=Z Y X W V U T S S R Q P O N(13 in reverse)

It is obvious from the above coding scheme that: B=Y,D=W and K=P….

Therefore BDIP will be coded as YWRK

 

5)Which code should be replaced in the question mark?  MILD:NKOH :: GATE : ?

 

Sol: Here, letters are coded by skipping letters in alphabetical order, I.e.., M=N (no

skipping)

I = (j) K (letters in the bracket are one’s skipped)

L = (mn) O

D = (efg) H

The skipping pattern is –1, -2 and –3

Therefore , G A T E will be coded as H C W I

 

6)If SPTFA stand for BLADE, how will you code BALE?

 

Sol: BLADE has been coded as SPTFA. You will see that all letters in the word BALE, which have to be coded are also there in the word BLADE. Hence all that need to be done is to choose the relevant code letters from the code word SPTFA. Thus B becomes S, A becomes T, L becomes P, and E becomes A. Therefore BALE will be coded as STPA.

 

7. If MAILED  is coded as NBJMFE, how will you code the word ACTED?

 

Sol : Here each letter stands for the next letter in the sequence. Therefore ACTED becomes BDUFE.

 

If TSEREVE and NOITACUDE stands for EVEREST and EDUCATION, how will you code REDFORT?

 

Sol: We can observe that the code is the reverse of the given word. The answer is

obviously TROFDER which is the reverse of REDFORT.

9. If LODES is coded as 46321, how will you code the word DOES?

Sol : Here you will observe that all the letters of DOES are included in the letters of  LODES , for which you have the code D = 3, O = 6, E = 2, S=1. Therefore, DOES = 3621.

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Direction Sense Test

Introduction:

There are four main directions – East, West, North and South as shown below:

There are four cardinal directions – North-East (N-E), North-West (N-W), South-East (S-E), and South-West (S-W) as shown below:

1. At the time of sunrise if a man stands facing the east, his shadow will be towards west.
2. At the time of sunset the shadow of an object is always in the east.
3. If a man stands facing the North, at the time of sunrise his shadow will be towards his left and at the time of sunset it will be towards his right.
4. At 12:00 noon, the rays of the sun are vertically downward hence there will be no shadow.

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Main types of questions are given below:

Type 1:

Siva starting from his house, goes 5 km in the East, then he turns to his left and goes 4 km. Finally he turns to his left and goes 5 km. Now how far is he from his house and in what direction?

Solution:

From third position it is clear he is 4 km from his house and is in North direction.

 

Type 2:

Suresh starting from his house, goes 4 km in the East, then he turns to his right and goes 3 km. What minimum distance will be covered by him to come back to his house?

Solution:

Type 3:

One morning after sunrise Juhi while going to school met Lalli at Boring road crossing. Lalli’s shadow was exactly to the right of Juhi. If they were face to face, which direction was Juhi facing?

Solution: In the morning sunrises in the east.

So in morning the shadow falls towards the west.

Now Lalli’s shadow falls to the right of the Juhi. Hence Juhi is facing South.

 

Type 4:

Hema starting from her house walked 5 km to reach the crossing of Palace. In which direction she was going, a road opposite to this direction goes to Hospital. The road to the right goes to station. If the road which goes to station is just opposite to the road which IT-Park, then in which direction to Hema is the road which goes to IT-Park?

Solution:

From II it is clear that the road which goes to IT-Park is left to Hema.