Reasoning Based LRDI
Reasoning-Based LRDI (Logical Reasoning and Data Interpretation) involves solving puzzles where the emphasis is more on logic and constraints than on heavy calculations. These problems usually provide information in the form of conditions, arrangements, or logical rules, and require step-by-step deduction to arrive at the correct solution.
Key Features of Reasoning-Based LRDI
- Data is qualitative or condition-based, not always numerical.
- Requires arrangement or classification, often in grids, tables, or seating layouts.
- Involves multi-variable relationships, like people vs subjects vs places.
- Focus is on logical consistency: ensuring all conditions are satisfied simultaneously.
Common Types of Reasoning-Based LRDI
| Type | Description | Example |
|---|---|---|
| Arrangement Puzzles | Placing people/items in order (rows, circles, schedules). | Six people sit around a table; A is between B and C. |
| Scheduling/Timetable Problems | Assigning events to days/times based on rules. | Five lectures to be scheduled Mon–Fri. |
| Grouping/Classification | Distributing people/items into categories. | 10 students divided into 3 clubs with restrictions. |
| Conditional Logic | Rules connect variables with “if–then” structures. | If A attends, then B cannot attend. |
| Matrix/Grids | Matching multiple attributes through elimination. | Four friends with different hobbies, jobs, and cities. |
How to Solve Reasoning-Based LRDI
- Extract all given conditions: List constraints clearly.
- Choose a framework: Use a table, grid, or diagram.
- Place definite information first: Start with fixed positions.
- Apply constraints step by step: Eliminate impossible options.
- Check for hidden logic: Conditional and relative statements often interlink.
- Cross-verify final arrangement: Every condition must be satisfied.
Conceptual Tips and Common Mistakes
- Don’t assume: Only use what’s explicitly stated.
- Start with strong clues: Fixed positions narrow down faster.
- Keep multiple possibilities: If unsure, track Case 1/Case 2.
- Watch out for negatives: “Not” conditions are just as important as positive ones.
- Time traps: These sets are logic-heavy; rushing often causes missed constraints.
Examples
Example 1 — Linear Arrangement
Five friends (A, B, C, D, E) sit in a row.
- A is left of B.
- C is between D and E.
- D is not at the end.
Correct order: A – B – E – C – D.
Example 2 — Scheduling Puzzle
Four subjects taught Mon–Thu: Physics, Chemistry, Math, Biology.
- Physics after Math.
- Chemistry before Biology.
- Math not on Monday.
Correct schedule: Mon = Chemistry, Tue = Math, Wed = Physics, Thu = Biology.
Example 3 — Grouping Puzzle
Four employees (A, B, C, D) assigned to Projects X, Y, Z with rules:
- A and B cannot work together.
- C must be in Project Y.
So: C = Y; if A = X, then B = Z (or vice versa).
Example 4 — Grid Puzzle
Four people (John, Mary, Raj, Sara) each have a different favorite color (red, blue, green, yellow).
- John ≠ red, Mary ≠ blue.
- Raj likes green.
- Sara does not like yellow.
Answer: Raj = green; then assign remaining logically → John = blue, Mary = yellow, Sara = red.