Quantitative Aptitude – Tables
(For Dadra & Nagar Haveli & Daman & Diu Police Constable Exam)
1. Simple Explanation
Tables are structured arrangements of data in rows and columns.
In aptitude tests they are used to:
| Show frequencies (e.g., age groups, marks) | Help you compare quantities (e.g., number of males vs females) |
| Allow quick calculations (percentages, averages, ratios) | Enable pattern recognition (trends, outliers) |
When you see a table, treat it like a mini‑database:
- Rows = individual items or categories.
- Columns = attributes of those items.
- Headings = provide the meaning of each column.
2. Key Points to Master
| # | Concept | How to Apply |
|---|---|---|
| 1. Read the headings first | Know what each column represents (units, categories, totals). | |
| 2. Identify the total row/column | Often the last row/column gives the grand total or overall percentage. | |
| 3. Check for missing values | If a row/column total is given, missing entries can be found by subtraction. | |
| 4. Find percentages | percentage = (part / whole) × 100. |
|
| 5. Compute averages | average = total sum / number of items. |
|
| 6. Work with ratios | Reduce fractions or compare two columns by ratio. | |
| 7. Be careful with units | e.g., “₹” vs “%” vs “number of people”. | |
| 8. Look for patterns | Increasing/decreasing trends, outliers, symmetry. |
3. Worked Example
Problem
A police training academy records the number of recruits who passed the physical test in three age groups:
| Age Group | Pass | Fail | Total |
|---|---|---|---|
| 18–20 | 24 | 6 | 30 |
| 21–23 | 30 | 10 | 40 |
| 24–26 | 18 | 12 | 30 |
| Total | 72 | 28 | 100 |
Questions
- What percentage of recruits passed the test?
- What is the average number of passes per age group?
- Find the number of recruits in the 24–26 age group who passed if the total passes were 70 instead of 72.
Solution
| Step | Explanation | Calculation | Result |
|---|---|---|---|
| 1. Pass percentage | total passes / total recruits × 100 |
72 / 100 × 100 |
72 % |
| 2. Average passes per age group | Sum of passes ÷ number of groups | 72 / 3 = 24 |
24 passes/group |
| 3. Recalculate 24–26 group passes | New total passes = 70. | ||
| First, find passes in other groups: 24–20 passes = 24, 21–23 passes = 30 → 54. | |||
| Subtract from new total. | 70 – 54 = 16 |
16 passes in 24–26 group |
Quick Tips for the Example
- Totals are handy: They allow you to verify calculations.
- Subtraction trick: When a grand total changes, keep other numbers fixed.
- Check consistency: Sum of row totals should equal grand total.
4. Quick Revision Summary
- Read headings → Understand data
- Use totals to find missing entries
- Percentages:
(part / whole) × 100 - Averages:
total / count - Ratios: Simplify or compare two columns
- Units matter: Convert if necessary before calculations
- Verify with cross‑checks: Row + column totals → overall total
Keep practicing with different table types (frequency, distribution, comparison) to build speed and accuracy. Good luck!