Coding-Decoding Questions for SSC MTS

Letter Coding (Shift Based)

A word is coded by shifting each letter forward or backward in the alphabet by a fixed number. For example, CAT becomes FDW if each letter is shifted +3 positions. Your job is to find the shift value from the given code pair, then apply the same shift to find the answer. Always check: is it forward (+) or backward (-)?

• Find shift by subtracting original letter position from coded letter position.
• If shift is positive, letters move forward in alphabet (A to D = +3).
• If shift is negative, letters move backward (D to A = -3).
• The same shift applies to ALL letters in the word.
• If you cross Z going forward, wrap around: Z+1 = A, Z+2 = B.

Reverse Alphabet Coding (Mirror Letters)

One of the most common tricks in SSC MTS: each letter is replaced by its mirror opposite in the alphabet. A(1) pairs with Z(26), B(2) pairs with Y(25), C(3) pairs with X(24), and so on. The rule is simple: Original Position + Coded Position = 27. Memorize this one formula and you can do these in seconds.

• A=Z, B=Y, C=X, D=W, E=V, F=U, G=T, H=S, I=R, J=Q, K=P, L=O, M=N.
• Formula: if original letter is at position p, coded letter is at position 27-p.
• This is called the EJOTY trick mirror — the alphabet folds at M-N.
• These questions look tricky but once you know the mirror rule they take 10 seconds.
• Sometimes only consonants or only vowels are reversed — read the question carefully.

Number Coding

Letters are assigned numbers, or numbers are assigned to represent words/objects. Two types appear in SSC MTS: (1) Each letter gets its alphabet position number (A=1, B=2... Z=26) and a word value is computed by adding or multiplying positions. (2) A table gives random number codes for specific words and you pick the right code for a new word.

• EJOTY shortcut: E=5, J=10, O=15, T=20, Y=25. Use as anchors to find any letter fast.
• For sum-based coding: add all letter positions of the word.
• For product-based coding: multiply all letter positions.
• For mixed: sometimes position+1 or position-1 is given — spot the pattern.
• In table-based number coding: treat each digit in the code as independently assigned to a letter, not the whole number.

Symbol and Substitution Coding

In these questions, words or objects are replaced by symbols, colors, or completely different words. For example: Apple is called Mango, Mango is called Banana, Banana is called Orange. Then the question asks: what do we eat that grows on trees? You must trace the chain carefully. Do not get confused by the new name — always find what the original real-world object maps to in the coded language.

• Read the substitution chain carefully from left to right.
• Answer what the real-world object is called in the new language, not what it actually is.
• Example trap: Banana grows on trees, but in the code Banana is called Orange — so answer is Orange.
• These require zero math — pure attention and careful reading.
• Common in SSC MTS as a quick-score question — do not overthink.

Conditional / Mixed Pattern Coding

Some SSC MTS questions mix two rules — for example, vowels stay the same but consonants are shifted, or every alternate letter is coded. Always identify the rule using the example pair given in the question before jumping to the answer. Spot what is changing and what is staying the same.

• Always decode the example pair first to understand the rule.
• Check vowels and consonants separately — the rule may differ for each.
• Check if letter order is reversed (CAT coded as TAC = reverse order).
• Sometimes numbers replace only vowels or only consonants.
• Never assume the same rule from a previous question — each question gives its own code.

• Confusing forward shift with backward shift — always verify direction using the given example pair, do not guess.
• Forgetting to wrap around the alphabet when shift crosses Z (forward) or A (backward). Z+3 = C, not ZC.
• In substitution coding, giving the original real-world answer instead of the coded name. The question asks what it is CALLED, not what it IS.
• Using EJOTY wrong — E=5 means the 5th letter is E, not that A=5. Anchor and count from the nearest EJOTY letter.
• Applying the rule from one question to the next question. Each Coding-Decoding question has its own independent rule.

• EJOTY = Every Journey Offers Twenty Years: E=5, J=10, O=15, T=20, Y=25. Learn this like a phone number — it saves 10 seconds per question.
• Mirror rule shortcut: A+Z=27, B+Y=27, always 27. So if you know one, subtract from 27 to get the other instantly.
• The SHIFT-VERIFY-APPLY habit: Step 1 find Shift from example, Step 2 Verify with one more letter, Step 3 Apply to answer word. Never skip Verify.
• Substitution coding = Name Tag game. A person wears a fake name tag. When asked about the real person, give the fake tag name, not their real name.

• SSC MTS typically gives 2-3 Coding-Decoding questions per paper. Difficulty is easy to medium — these are scoring questions, target all correct.
• Letter shift and mirror coding appear most frequently. Practice alphabet positions until you can recall any letter's number in under 2 seconds.
• In recent MTS papers, substitution coding (word replacement chains) appeared once per set. These take under 20 seconds if you stay calm.
• Avoid writing out the full alphabet during the exam — waste of time. Use EJOTY anchors to count only 1-4 steps from the nearest anchor.
• If a question looks unusual or mixed, spend 15 seconds identifying the pattern using the given pair before solving. Attempting without spotting the rule is the main reason for wrong answers.