Percentage-Based Analysis
SSC GD Self-Paced Course
Percentage questions are a core part of Quantitative Aptitude in exams like SSC, Delhi Police, and other competitive exams. They test your ability to calculate ratios, compare quantities, and analyze data effectively.
1. What is Percentage?
Definition:
A percentage is a way of expressing a number as a fraction of 100. It is
denoted using the symbol %.
Formula:
Percentage = (Part / Whole) × 100
Purpose:
Express proportions clearly
Compare quantities
Calculate profit, loss, discount, and growth rates
2. Common Types of Percentage Problems
| Type | Description | Example |
|---|---|---|
| Simple Percentage | Calculate % of a given quantity | What is 20% of 150? |
| Increase / Decrease | Find % change between two values | Price rises from 200 to 250 |
| Profit / Loss | Express gain or loss as % of cost | Cost = 100, Selling = 120 |
| Discount | % reduction from marked price | Item marked ₹500, discount 10% |
| Population / Data Analysis | Analyze % from data tables or charts | Population of males = 60% of total |
3. Key Formulas
| Concept | Formula |
|---|---|
| Percentage | (Part / Whole) × 100 |
| Value from Percentage | Value = (Percentage × Whole) / 100 |
| Percentage Increase | [(New - Old) / Old] × 100 |
| Percentage Decrease | [(Old - New) / Old] × 100 |
| Successive Percentage Change | Net % change = P₁ + P₂ + (P₁×P₂)/100 |
4. Tips for Solving Percentage Questions
Always identify the whole before calculating percentage
Convert fractions to percentages if needed
Use approximation for faster calculation in exams
Be careful with increase vs decrease to avoid sign errors
Check units (e.g., kg, rupees, population) to interpret data correctly
Practice previous year questions to recognize patterns
Learn percentage equivalents of common fractions
Use cross-multiplication for quick calculations
🧠 Practice Section: 15 Questions (With Answers)
Each Q followed by its Answer (SSC style). Click on "View Answer" to check your understanding.
Q1. Find 25% of 400.
View Answer
400 × (25/100) = 100
Q2. If a price increases from ₹200 to ₹250, find % increase.
View Answer
[(250-200)/200] × 100 = 25%
Q3. A shopkeeper sold an item for ₹120, costing ₹100. Find profit %.
View Answer
Profit = 20; Profit % = (20/100) × 100 = 20%
Q4. The population of a city is 50,000. Males are 60%. Find number of males.
View Answer
50,000 × 60% = 30,000
Q5. An article marked ₹500 is sold at 10% discount. Selling price?
View Answer
SP = 500 - 10% of 500 = 500 - 50 = ₹450
Q6. If a student scored 180 out of 200, what is the percentage?
View Answer
(180/200) × 100 = 90%
Q7. A company's revenue increased from ₹1,00,000 to ₹1,20,000. % increase?
View Answer
[(1,20,000-1,00,000)/1,00,000] × 100 = 20%
Q8. A population decreased from 80,000 to 72,000. % decrease?
View Answer
[(80,000-72,000)/80,000] × 100 = 10%
Q9. Successive increases of 10% and 20% on a salary of ₹10,000. New salary?
View Answer
10,000 × 1.10 × 1.20 = ₹13,200
Q10. 40% of a number is 120. Find the number.
View Answer
120 ÷ 0.4 = 300
Q11. A student gets 75% in exam with 300 marks. Marks obtained?
View Answer
300 × 75% = 225
Q12. An item costs ₹400. After 15% discount, find SP.
View Answer
SP = 400 - 15% of 400 = 400 - 60 = ₹340
Q13. Population of a town 50,000. 20% are children. Number of children?
View Answer
50,000 × 20% = 10,000
Q14. A salary decreases by 12%. If original salary ₹25,000, new salary?
View Answer
25,000 - 12% of 25,000 = 25,000 - 3,000 = ₹22,000
Q15. A shopkeeper increases price by 25% and then gives 10% discount. Net change?
View Answer
Net = 1.25 × 0.90 = 1.125 → 12.5% net increase
✅ SSC GD Exam Strategy
🟢 Memorize common percentage-fraction conversions (25% = 1/4, 50% = 1/2, etc.)
🟢 Practice mental percentage calculations for speed
🟢 Master successive percentage change formulas
🟢 Learn to identify base value in percentage problems
🟢 Time yourself - aim for 30-45 seconds per percentage problem
You've completed Percentage-Based Analysis!
SSC GD Tip: Mastering percentage calculations is fundamental for solving various quantitative problems efficiently. Remember that percentages are essentially fractions with denominator 100. Practice converting between percentages, fractions, and decimals. Pay special attention to profit-loss, discount, and successive percentage change problems as they frequently appear in exams. Regular practice with previous year SSC GD questions will build your speed and accuracy in solving percentage-based problems.
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