📚 Study Notes – Quantitative Aptitude
Topic: Tables
Exam: Dadra & Nagar Haveli & Daman & Diu Forest Guard
Subject: Quantitative Aptitude
Section: Tables
1️⃣ Simple Explanation
Tables are a compact way to represent data or a set of numbers in a grid.
They are used in aptitude tests to:
- Display a collection of numbers (e.g., monthly rainfall, population growth).
- Save time – you don’t have to write long calculations.
- Ask questions that test your ability to read, interpret, and manipulate data.
Why they matter:
In the exam you will often be given a table and asked to:
- Find a missing entry.
- Compute a sum, average, ratio, or percentage.
- Locate a specific value (first/last occurrence, max/min, etc.).
2️⃣ Key Points & Tips
| # | Point | Tip |
|---|---|---|
| 1 | Understand the heading | The first row/column often contains labels (e.g., months, categories). |
| 2 | Look for patterns | Sequences, arithmetic progression, fractions, ratios, or repeated cycles. |
| 3 | Check for cumulative data | Some tables give cumulative values (e.g., “Cumulative rainfall”). |
| 4 | Use “back‑sweep” | If a row/column is missing a value, back‑track using other rows/columns. |
| 5 | Divide & conquer | Break the table into smaller sections (rows, columns, sub‑tables). |
| 6 | Check unit consistency | Ensure units (kg, %, days) match across the table. |
| 7 | Quick mental math | For simple arithmetic (addition, subtraction, multiplication by 10, 5, 2). |
| 8 | Avoid reading errors | Double‑check the row/column order; mistakes often come from mis‑reading the table. |
| 9 | Use abbreviations | e.g., “Avg.” = average, “Diff.” = difference. |
| 10 | Cross‑reference | If a table has both row totals and column totals, they should match. |
3️⃣ Worked Example
📃 Problem
| Month | Rainfall (mm) | Cumulative Rainfall (mm) |
|---|---|---|
| Jan | 120 | 120 |
| Feb | 80 | 200 |
| Mar | 150 | 350 |
| Apr | 90 | ? |
| May | 110 | 600 |
Question: What is the rainfall in April, and what is the cumulative rainfall for April?
📌 Solution Steps
-
Identify the unknowns
- Rainfall in April (call it R₄)
- Cumulative rainfall after April (call it C₄)
-
Use the cumulative column
Cumulative rainfall is a running total.
So:C₄ = C₃ + R₄Where C₃ = 350 mm (from March).
-
Find C₄ using the given May cumulative value
We know that after May, cumulative = 600 mm.
Therefore:C₅ = C₄ + R₅ 600 = C₄ + 110 C₄ = 600 – 110 = 490 mm -
Solve for R₄
C₄ = C₃ + R₄ 490 = 350 + R₄ R₄ = 490 – 350 = 140 mm
📦 Result
| Month | Rainfall (mm) | Cumulative Rainfall (mm) |
|---|---|---|
| Apr | 140 | 490 |
4️⃣ Quick Revision Summary
| Category | What to Check | Quick Tip |
|---|---|---|
| Reading | Row/column labels, units, totals | Pause, read labels twice |
| Pattern | Arithmetic, geometric, cumulative | Spot the next number |
| Missing value | Use adjacent rows/columns | Work backwards if needed |
| Totals | Sum of a row/column equals the given total | Verify with quick addition |
| Ratios/Percentages | Compare two cells | Multiply by 100 for percent |
| Mental Math | Multiply/divide by 10, 5, 2 | Use doubling/tripling tricks |
🔑 Final Tips
- Practice with real data – e.g., rainfall, temperature, population growth.
- Time yourself – tables are usually quicker if you read them efficiently.
- Double‑check – one small reading mistake can lead to a wrong answer.
- Keep a handy cheat sheet – write down common patterns (e.g., “if cumulative = 500 and next month = 120, previous month = 380”).
Good luck with your preparation! Happy studying!