Coding - Decoding
🔒 Log in to trackLanguage (sentence) coding with common words
🔒 Log in to trackWhole sentences are written as code words, like 'good morning sir' = 'ta pa ni'. The code words are jumbled, so you never match them by position. Compare sentences: a word shared by two sentences has the code word they share.
What language coding is
A whole sentence is written in a code language. 'good morning sir' becomes 'ta pa ni'.
You get two or three such sentences with their codes. You must find the code of a word, or the meaning of a code.
Rule: The code order is jumbled. 'good morning' = 'ta pa' does not mean good = ta. Never match by position.
Intersect, then subtract
- Intersect. Find every sentence that contains your word. The word's code is among the code words those sentences share.
- Subtract. Remove codes already fixed for other words. If one code is left, that is the answer.
Example: 'sun is hot' = 'ta mo ri' and 'sun is bright' = 'ri ze mo'. 'sun is' is common, so 'mo ri' belongs to them. The leftover word 'hot' takes the leftover code ta.
When the answer is "cannot be determined"
Sometimes two codes still fit after all the subtraction. Then stop. The answer is cannot be determined.
'sky is blue' = 'ta pa ka' and 'sea is deep' = 'pa za la'. Only 'is' is common, so is = pa. 'blue' can be 'ta' or 'ka'. Both are possible.
The same happens in the 'sun is hot' example above. 'sun' can be 'mo' or 'ri'. We know the pair, not which is which.
Watch: Picking one of the two codes is the classic wrong answer. The option "cannot be determined" is there for exactly this case.
A full question, start to finish
"'good morning sir' is 'ta pa ni', 'good night sir' is 'pa ni ro' and 'night is dark' is 'ro ki su'. What is the code for 'morning'?"
- Lines 1 and 2 share 'good' and 'sir'. Their codes are 'pa' and 'ni' in some order.
- Lines 2 and 3 share only 'night'. The common code is 'ro', so night = ro.
- Line 1 is now short of one word: 'morning'. It takes the leftover code 'ta'.
Answer: ta. One fixed code unlocked the rest, line by line.
Three sentences
More sentences give more information. Work in this order:
- Find words common to two sentences.
- Find the codes common to the same two sentences.
- A word common to two different pairs is fixed by the code common to both pairs.
- Subtract the fixed codes and assign the leftovers.
With three good sentences, every word usually gets its own code.
Phrases and digit codes
- To code a phrase like 'sweet home', find each word's code. Then write them in the order the phrase asks.
- Some papers use digits: 'come home' = '1 2' and 'home sweet' = '2 3'. Then home = 2, come = 1 and sweet = 3. The method is the same.
Reverse questions
"What does 'ra' mean?" Work exactly the same way, then read your mapping backwards. If sing = ra, then 'ra' means sing.
Tip: Check your final mapping on every sentence. Each word must have its code in that sentence's code line.
Question types you will see
Each type: how to recognise it, the method step by step, and one question to try.
Two sentences with common words
Two sentence–code pairs share one or two words. This is the basic form.
Find the words common to both sentences; their codes are the common codes.
In one sentence, the leftover word takes the leftover code.
Read the asked word from your mapping.
Codes of common words must sit in both code lines, so the leftover is forced.
In a code language, 'delhi is big' is 'ja pa ni' and 'mumbai is big' is 'sa pa ni'. What is the code for 'delhi'?
Show solutionHide solution
'is big' is common, and 'pa ni' is common.
In the first sentence, 'delhi' takes the leftover code.
ja
Three sentences, step-by-step elimination
Three sentence–code pairs; the asked word needs two rounds of subtraction.
Compare each pair of sentences for common words and codes.
A word common to two pairs gets the code common to both.
Subtract the fixed codes from the asked word's sentence.
The last code left is the answer.
Each fixed code shrinks the leftovers; three sentences usually finish the job.
In a code language, 'train runs fast' is 'la jo me', 'bus runs fast' is 'la jo fi' and 'fast train' is 'me jo'. What is the code for 'bus'?
Show solutionHide solution
Sentences 1 and 2 share 'runs fast' and 'la jo'.
Sentences 1 and 3 share 'fast train' and 'me jo'.
'fast' is in both pairs, so fast = jo. Then runs = la and train = me.
Sentence 2 leaves bus with the last code.
fi
Cannot be determined (two codes left)
The asked word appears in only one sentence, and two codes there are still unclaimed.
Fix every code you can with common words.
Count the codes still possible for the asked word.
If two remain, answer 'cannot be determined'.
Jumbled order makes both leftover codes equally possible.
In a code language, 'sky is blue' is 'ta pa ka' and 'sea is deep' is 'pa za la'. What is the code for 'blue'?
Show solutionHide solution
Only 'is' is common, so is = pa.
'sky' and 'blue' share 'ta' and 'ka'.
Nothing tells them apart.
Cannot be determined
Phrase codes and digit codes
The question asks for the code of a phrase, or the codes are digits like '1 2'.
Find each word's code by the usual method.
Write the codes in the phrase's own word order.
Treat digit codes exactly like word codes.
A phrase code is just its word codes written in the asked order.
In a code language, 'come home' is '1 2' and 'home sweet' is '2 3'. What is the code for 'sweet home'?
Show solutionHide solution
'home' is common and '2' is common, so home = 2.
Then come = 1 and sweet = 3.
'sweet home' = sweet, then home.
3 2
Reverse: what does the code mean?
The question gives a code word and asks which English word it stands for.
Fix the mapping word by word with intersect and subtract.
Find the given code in your mapping.
Give the English word as the answer.
The mapping works both ways; only the reading direction changes.
In a code language, 'birds fly' is 'lo pe', 'fly high' is 'pe ni' and 'birds sing' is 'lo ra'. What does 'ra' mean?
Show solutionHide solution
birds = lo (sentences 1 and 3). fly = pe (sentences 1 and 2).
In 'birds sing' = 'lo ra', sing takes 'ra'.
sing
Shortcuts that save time
For a word, take the code words shared by all sentences that contain it. Remove codes already fixed for other words. One left is the answer; two left means cannot be determined.
'sun is hot' = 'ta mo ri' and 'sun is bright' = 'ri ze mo'. What is the code for 'hot'?
Show solutionHide solution
'sun is' is common to both, and 'mo ri' is common to both codes.
In the first sentence, 'hot' takes the leftover code.
ta
Mistakes to avoid
Where most students lose marks on this subtopic.
Matching code words by position.
The order is jumbled. Match by common words and common codes.
Picking one of two equally possible codes.
Answer 'cannot be determined' when two codes still fit.
Using a code already fixed for another word.
Each code belongs to one word only. Subtract fixed codes first.
Writing a phrase code in the order you found the words.
Write it in the phrase's own word order.
Stopping after two sentences when a third one is given.
Use every sentence. The third one often breaks the tie.
Quick revision
Read this the night before the exam.
Never match by position; the code order is jumbled.
A word's code is among the codes shared by every sentence containing it.
Subtract fixed codes; one code left is the answer.
Two codes still possible → cannot be determined.
Phrase codes follow the phrase's word order; digits work the same way.
Check the final mapping on every sentence.
Practice: 12 questions
Sets of 10, mixed across the question types above. Every answer has a step-by-step explanation.
Topic test · 12 questions
Suggested time 8 min · wrong answers go to your mistake notebook automatically.