Percentage Conversion & Calculation
SSC GD Exam Preparation - Quantitative Aptitude
A percentage is a number expressed out of 100.
Percentage = (Value / Total) × 100
Example:
If you score 45 marks out of 50
(45/50) × 100 = 90%
🔹 2. Conversion Between Fractions, Decimals & Percentages
(A) Fraction → Percentage
(a/b) × 100%
1/4 = 25%
3/5 = 60%
2/25 = 8%
Common Conversions Table
| Fraction | Percentage |
|---|---|
| 1/2 | 50% |
| 1/3 | 33.33% |
| 1/4 | 25% |
| 1/5 | 20% |
| 1/8 | 12.5% |
| 1/10 | 10% |
(B) Percentage → Fraction
Divide by 100
40% = 40/100 = 2/5
(C) Decimal → Percentage
Multiply by 100
0.5 = 50%
(D) Percentage → Decimal
Divide by 100
45% = 0.45
🔹 3. Percentage Increase & Decrease
Percentage Increase
(Increase / Original) × 100
Example:
Price increases from 80 to 100
Increase = 20
(20/80) × 100 = 25%
Percentage Decrease
(Decrease / Original) × 100
Example:
Price decreases from 200 to 160
Decrease = 40
(40/200) × 100 = 20%
🔹 4. Successive Percentage Formula
A + B + (A × B)/100
Example:
Increase 20% and 30%:
20 + 30 + (20 × 30)/100 = 56%
🔹 5. Percentage of Quantity
Example 1:
20% of 150
(20/100) × 150 = 30
Example 2:
12% of 450
0.12 × 450 = 54
🔹 6. Finding Number from Percentage
If x% of a number = y, then Number = (y × 100)/x
Example:
30% of number = 45
(45 × 100)/30 = 150
🔹 7. Percentage Comparison
(A - B)/B × 100
Example:
A = 60, B = 40
Difference = 20
(20/40) × 100 = 50%
🧠15 Practice Questions with Answers (SSC Level)
Test your percentage concepts with these SSC GD level practice questions. Click on "View Answer" to check your understanding.
Q1. What is 35% of 280?
View Answer
35% of 280 = (35/100) × 280 = 98
Q2. Convert 5/8 into percentage.
View Answer
5/8 = 0.625 = 62.5%
Q3. Convert 0.72 into percentage.
View Answer
0.72 × 100 = 72%
Q4. What percent of 150 is 30?
View Answer
(30/150) × 100 = 20%
Q5. A number is increased from 400 to 500. Find % increase.
View Answer
Increase = 100, (100/400) × 100 = 25%
Q6. Price decreases from 750 to 525. Find % decrease.
View Answer
Decrease = 225, (225/750) × 100 = 30%
Q7. A number is first increased by 20% and then increased by 10%. Find net increase.
View Answer
20 + 10 + (20 × 10)/100 = 32%
Q8. 28% of a number is 84. Find the number.
View Answer
Number = (84 × 100)/28 = 300
Q9. A is 75 and B is 60. A is what percent more than B?
View Answer
Difference = 15, (15/60) × 100 = 25%
Q10. What is 18% of 450?
View Answer
18% × 450 = 81
Q11. Convert 225% into a fraction.
View Answer
225% = 225/100 = 9/4
Q12. A shopkeeper gives 20% discount on ₹2500. Find the selling price.
View Answer
Discount = 20% of 2500 = 500, SP = 2500 − 500 = ₹2000
Q13. In a class, girls are 40%. If girls = 36, find total students.
View Answer
Total = (36 × 100)/40 = 90
Q14. A salary is decreased by 15% and then increased by 20%. Find net % change.
View Answer
Net change = (-15 + 20 + (-15 × 20)/100) = 5 - 3 = 2% increase
Q15. 75% of a number is 120. Find the number.
View Answer
Number = (120 × 100)/75 = 160
✅ SSC GD Exam Strategy
🟢 Memorize common fraction-percentage conversions
🟢 Practice successive percentage formula for quick calculations
🟢 Master percentage increase/decrease applications
🟢 Learn to quickly find original number from percentage
🟢 Time yourself - aim for 30-45 seconds per percentage question
You've completed Percentage Conversion & Calculation Concepts!
SSC GD Tip: Percentage is one of the most important topics in the quantitative section. Focus on mastering the basic conversions between fractions, decimals, and percentages. Remember the key formulas for percentage increase/decrease and successive percentages. Practice mental calculations for common percentages (like 12.5%, 37.5%, 62.5%, etc.) to save time. Regular practice with previous year SSC GD questions will build your speed and accuracy in solving percentage problems quickly.
Master Percentage Calculations for SSC GD Exam!
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