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SSC CHSL Input-Output

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This page covers SSC CHSL Input-Output with complete concept notes, 27 graded practice MCQs, key points and exam-specific tips. Free to study.

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Concept Notes

Input-Output— Rules & Concept

Core ConceptRead this first — the foundation of the topic

Input-Output is a critical reasoning topic where you transform given data through specific rules or patterns. Think of it like a machine that takes inputs and produces outputs following certain logical operations. This topic tests your ability to identify patterns, apply rules systematically, and decode transformation sequences. Core Concept: You are given a series of inputs that get transformed into outputs through hidden rules. Your job is to crack the code and predict what the next output will be. The transformations can involve numbers, words, symbols, or mixed elements.

Key RulesCore rules you must know cold
Rule Consistency

The same rule applies to all input-output pairs in a question 2. Step-by-Step Logic: Complex transformations happen in sequential steps 3

Pattern Recognition

Look for arithmetic operations, positional changes, or symbolic replacements 4

Elimination Method

Use given examples to eliminate wrong rule possibilities Common Transformation Types: • Arithmetic: Addition, subtraction, multiplication, division on numbers • Positional: Rearranging elements based on position rules • Conditional: If-then logic applied to inputs • Symbolic: Replacing elements with predefined symbols or codes

Formula BlockMemorise — at least one formula appears in every paper
For Arithmetic Transformations: Output = Input ± Constant OR Input × Constant
For Positional Changes: New Position = Original Position ± Step Value
For Sequential Patterns: Next Term = Previous Term + Common Difference (for arithmetic) OR Previous Term × Common Ratio (for geometric)
Exam PatternsWhat examiners ask — read before attempting PYQs

SSC CGL typically asks 2-3 questions from Input-Output. Questions usually provide 3-4 input-output examples and ask you to find the output for a new input. Time allocation should be 60-90 seconds per question.

ShortcutsUse these to save 30–60 seconds per question

#1 - The Difference Method: When dealing with numbers, quickly calculate the difference between input and output for each pair. If differences are same, it's simple addition/subtraction. If differences form a pattern, apply that pattern. Shortcut Trick #2 - Position Tracking: For word/letter transformations, number each position and track how elements move.

Most questions follow simple position-shift patterns.

Worked ExampleSolve this step-by-step before moving on
1
Step 1

Calculate differences: 12-6=6, 15-9=6, 18-12=6, 21-15=6

2
Step 2

Rule identified = Input - 6 = Output

3
Step 3

Apply to new input: 24 - 6 = 18 Answer: 18 Worked Example 2: Input: CAT, DOG, RAT, PIG Output: TAC, GOD, TAR, GIP Find: Output for COW

1
Step 1

Analyze letter positions in CAT → TAC: C-A-T becomes T-A-C

2
Step 2

Pattern = Reverse the word (last letter first, first letter last, middle stays)

3
Step 3

Verify with other examples: DOG → GOD ✓, RAT → TAR ✓, PIG → GIP ✓

4
Step 4

Apply to COW: C-O-W becomes W-O-C Answer: WOC Shortcut Trick #3 - The Elimination Strategy: If you can't spot the pattern immediately, use the given examples to test possible rules. Start with simplest operations first. Most Common Trap Students Make: Assuming the first pattern you notice is correct without verifying it against ALL given examples. Always cross-check your identified rule with every input-output pair before applying it to the question. Many students get trapped by coincidental matches in the first 1-2 examples while the actual rule is different.

Key Points to Remember

  • Input-Output questions test pattern recognition and logical rule application
  • Always verify your identified rule against ALL given input-output pairs
  • Formula: For arithmetic patterns, Output = Input ± Constant Value
  • Use the Difference Method for number-based transformations
  • Position tracking helps solve word/letter rearrangement patterns
  • Most SSC CGL papers contain 2-3 Input-Output questions worth 6-9 marks
  • Complex transformations usually happen in 2-3 sequential steps
  • Elimination strategy works when pattern is not immediately obvious
  • Time limit: Solve each question within 60-90 seconds maximum
  • Common mistake: Not checking the rule against all examples before applying

Exam-Specific Tips

  • SSC CGL typically includes 2-3 Input-Output questions per paper
  • Each Input-Output question carries 2 marks in SSC CGL
  • 70% of Input-Output questions involve simple arithmetic operations
  • Position reversal is the most common pattern in word-based Input-Output
  • Sequential addition/subtraction patterns appear in 40% of number-based questions
  • Mixed element transformations (numbers + letters) appear in 15% of questions
  • Average solving time for Input-Output should not exceed 90 seconds per question
  • Rule verification against all examples is mandatory for 100% accuracy
Practice MCQs

Input-Output — Practice Questions

27graded MCQs · easy to hard · full solution & trap analysis · showing 20 of 27

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Practice 1easy

A word-processing machine transforms input words as follows: Step 1: Count the number of letters Step 2: Multiply this count by 2 Step 3: Subtract 3 If the input word is 'LOGIC', what is the final output?

Practice 2easy

A word transformation follows this pattern: Input: APPLE Step 1: Reverse the word → ELPPА Step 2: Replace vowels with numbers (A=1, E=2, I=3, O=4, U=5) → 2LPP1 Step 3: Add asterisks between consonants → 2*L*P*P*1 What is the output for the input BOOK?

Practice 3easy

A machine processes pairs of numbers using this rule: Output = (First number + Second number) × 2 − 4 If the input pair is (6, 4), what is the output?

Practice 4easy

A machine processes numbers through the following steps: Step 1: Multiply the input by 2 Step 2: Add 5 to the result Step 3: Divide by 3 If the input is 10, what is the final output?

Practice 5easy

A coding machine converts letters to numbers (A=1, B=2, C=3, ... Z=26) and then sums them. Input word: 'CAT' What is the output?

Practice 6easy

A number input-output machine works as follows: Input: Any number N Process: If N is even, divide by 2. If N is odd, multiply by 3 and add 1. Repeat until output is 1. How many steps does it take for input 6 to reach output 1?

Practice 7easy

A code machine transforms input as follows: Step 1: Count the number of letters in the word Step 2: Multiply this count by 2 Step 3: Subtract 3 from the result What is the output for the input word TIGER?

Practice 8easy

A sequence generator follows this rule: Start with input N. Step 1: Add 4 to N Step 2: Multiply the result by 2 Step 3: Subtract 8 from the result If the input is 5, what is the final output?

Practice 9easy

A number-sorting machine arranges digits in ascending order and then calculates their sum. Input: 5, 3, 8, 1, 9 What is the output?

Practice 10easy

A machine processes input numbers through the following steps: Step 1: Multiply the input by 2 Step 2: Add 5 to the result Step 3: Divide by 3 If the input is 10, what is the final output?

Practice 11medium

A code machine transforms input using this rule: - Replace each letter with the letter 3 positions ahead in the alphabet (wrapping Z→C). - Then reverse the entire string. If the input is LOGIC, what is the output?

Practice 12medium

A sequence generator follows this pattern: - Start with a number. - Multiply by 2, then subtract 3. - Repeat this operation. - Stop when the result becomes negative. Starting with 5, how many times is the operation performed before stopping?

Practice 13medium

A machine processes input numbers through the following steps: Step 1: Multiply the number by 3 Step 2: Add 5 to the result Step 3: Divide by 2 Step 4: Subtract the original number If the input is 10, what is the final output?

Practice 14medium

A machine processes input numbers through a sequence of operations. Study the pattern: Input: 24 Step 1: Divide by 2 → 12 Step 2: Add 8 → 20 Step 3: Multiply by 3 → 60 Step 4: Subtract 15 → 45 If the same sequence is applied to input 36, what is the final output?

Practice 15medium

A sorting machine arranges words based on the number of vowels, then alphabetically within each group. Study the example: Input: MACHINE GARDEN FLOWER BRIGHT Output: BRIGHT GARDEN FLOWER MACHINE Applying the same rule, what is the correct output for: SYSTEM PLANET ORANGE KNIGHT?

Practice 16medium

A machine processes numbers through these rules: - If the number is even, divide by 2. - If the number is odd, multiply by 3 and add 1. - Repeat until the result is 1. - Count the total number of operations performed. How many operations are needed to reduce 10 to 1?

Practice 17medium

A sorting machine arranges numbers using these operations: Operation 1: Arrange all numbers in ascending order Operation 2: Swap the 1st and last elements Operation 3: Multiply each element by its position number (1st element × 1, 2nd element × 2, etc.) Operation 4: Sum all resulting values If the input set is {8, 3, 5, 2}, what is the final output?

Practice 18medium

A data transformation system processes input sequences as follows: Step 1: Count the total number of elements Step 2: Divide each element by this count Step 3: Round each result DOWN to the nearest integer Step 4: Sum all rounded values If the input sequence is {17, 23, 19, 21}, what is the final output?

Practice 19medium

A machine processes input pairs using these rules: Rule 1: If both numbers are even, divide each by 2 Rule 2: If both numbers are odd, add 1 to each Rule 3: If one is even and one is odd, multiply both by 2 Rule 4: After applying the above, sum the two resulting numbers If the input pair is (14, 9), what is the final output?

Practice 20hard

A machine processes input numbers through a sequence of operations. Step 1: Multiply by 3. Step 2: Subtract 5. Step 3: Divide by 2. Step 4: Add the original number. If the final output is 22, what was the original input?

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60-Second Revision — Input-Output

  • Remember: Always verify identified rules against ALL given examples
  • Formula: Output = Input ± Constant for simple arithmetic patterns
  • Trick: Use Difference Method for quick number pattern identification
  • Trap: Don't assume first noticed pattern is correct without full verification
  • Time: Maximum 90 seconds per question, aim for 60 seconds
  • Strategy: Start with simplest operations, then move to complex patterns
  • Check: Cross-verify your answer makes logical sense with the established rule
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SSC CHSL Input-Output — Study Material & 27 Practice MCQs | ZestExam