Input Output
Input-Output questions involve a process where a set of input (words, numbers, or a combination) is rearranged or transformed step by step according to a fixed rule. The task is to identify the underlying rule and either complete the missing steps, predict the final arrangement, or determine what the input/output will look like at a certain stage.
These problems test logical reasoning, observation skills, and the ability to decode stepwise transformations.
Types of Input-Output Problems
| Type | Description | Example |
|---|---|---|
| Word Arrangement | Words are rearranged alphabetically, by length, or by some order. | Input: “cat dog bat” → Output: “bat cat dog” (alphabetical). |
| Number Arrangement | Numbers are ordered ascending, descending, or by another logic (like odd-even, squares). | Input: 45, 12, 78 → Output: 12, 45, 78 (ascending). |
| Alphanumeric Arrangement | Words + numbers are rearranged using a combined rule. | Input: “X3 Y1 Z2” → Output: “Y1 Z2 X3”. |
| Mathematical Operation | Numbers undergo step-by-step arithmetic changes. | Input: 12, 24 → Step 1: +2 each → Output: 14, 26. |
| Code/Pattern-Based | A mix of letters/numbers transformed with a hidden code. | Input: “ABC123” → Output: “BCD234” (+1 shift). |
How to Solve Input-Output Questions
- Observe Input and Output carefully: Compare them step by step to find the transformation.
- Identify the rule: Check if it involves ordering, arithmetic, shifting, or coding.
- Test the rule consistently: Apply it to all elements—rules never change midway.
- Trace intermediate steps: Write stepwise outputs to confirm.
- Answer the requirement: Depending on the question, provide the next step, final step, or specific stage.
Conceptual Tips and Common Mistakes
- One rule per step: Each step usually applies the same transformation across elements.
- Don’t rush with assumptions: Test the rule on multiple elements before finalizing.
- Watch for compound rules: Sometimes arrangement + arithmetic happens together.
- Practice speed: Input-Output questions are often lengthy—step tracking saves time.
- Check direction: Arrangements may be from left to right or right to left.
Examples
Example 1 — Word Arrangement
Input: “apple zebra cat dog”
Step 1: Arrange alphabetically → apple cat dog zebra
Answer: Final output = apple cat dog zebra.
Example 2 — Number Arrangement
Input: 42, 11, 89, 65
Step 1: Arrange ascending → 11, 42, 65, 89
Answer: Final output = 11, 42, 65, 89.
Example 3 — Alphanumeric Arrangement
Input: “B2 A1 C3”
Step 1: Arrange by number → A1 B2 C3
Answer: Final output = A1 B2 C3.
Example 4 — Mathematical Operation
Input: 5, 10, 15
Step 1: Add 2 to each → 7, 12, 17
Step 2: Multiply each by 2 → 14, 24, 34
Answer: Final output = 14, 24, 34.