Percentage Notes for SSC CGL
The word Percentage is derived from the Latin term "Per Centum" which means "out of one hundred". Percentage is one of the most important topics in SSC CGL, CHSL, MTS, CPO, GD and Railway examinations.
1. What is Percentage?
A percentage is a way of expressing a number as a fraction of 100.
- 10% means 10 out of 100
- 25% means 25 out of 100
- 50% means 50 out of 100
- 100% means complete quantity
2. Important Fraction to Percentage Table
| Fraction | Percentage |
|---|---|
| 1/2 | 50% |
| 1/3 | 33.33% |
| 2/3 | 66.67% |
| 1/4 | 25% |
| 3/4 | 75% |
| 1/5 | 20% |
| 2/5 | 40% |
| 3/5 | 60% |
| 4/5 | 80% |
| 1/8 | 12.5% |
| 3/8 | 37.5% |
| 5/8 | 62.5% |
| 7/8 | 87.5% |
3. Percentage to Fraction Conversion
| Percentage | Fraction |
|---|---|
| 10% | 1/10 |
| 20% | 1/5 |
| 25% | 1/4 |
| 40% | 2/5 |
| 50% | 1/2 |
| 60% | 3/5 |
| 75% | 3/4 |
| 80% | 4/5 |
| 90% | 9/10 |
4. Finding Percentage of a Number
Example 1
Find 25% of 800.
25 × 800 ÷ 100
= 200
Answer = 200
Example 2
Find 12.5% of 480.
12.5% = 1/8
480 ÷ 8
= 60
Answer = 60
5. What Percent One Number Is Of Another
Example
40 is what percent of 80?
(40 ÷ 80) × 100
= 50%
Answer = 50%
6. Percentage Increase
Example
Salary increases from ₹25,000 to ₹30,000.
Increase = ₹5,000
5000 ÷ 25000 × 100
= 20%
Answer = 20% Increase
7. Percentage Decrease
Example
Price decreases from ₹500 to ₹450.
Decrease = ₹50
50 ÷ 500 × 100
= 10%
Answer = 10% Decrease
8. SSC Shortcut Tricks
Shortcut 1
If A is 25% more than B.
A = 125
B = 100
Difference = 25
B is 20% less than A.
Shortcut 2
If A is 50% more than B.
A = 150
B = 100
Difference = 50
50 ÷ 150 × 100
= 33.33%
B is 33.33% less than A.
Shortcut 3
Increase 20% then decrease 10%.
Net Change Formula:
A + B + AB/100
20 + (-10) + (20×-10)/100
= 8%
Answer = 8% Increase
9. SSC Previous Year Questions
SSC CGL PYQ 1
A number is increased by 20% and then reduced by 20%. Find the net effect.
100 → 120
120 → 96
Loss = 4%
Answer = 4% Loss
SSC CGL PYQ 2
A student scored 360 marks out of 450. Find the percentage.
360 ÷ 450 × 100
= 80%
Answer = 80%
SSC CGL PYQ 3
Population increases from 40,000 to 50,000. Find the percentage increase.
Increase = 10,000
10000 ÷ 40000 × 100
= 25%
Answer = 25%
10. Practice Questions
- Find 35% of 560.
- 80 is what percent of 400?
- A salary increases from ₹40,000 to ₹50,000. Find increase %.
- Price decreases from ₹1200 to ₹960. Find decrease %.
- A is 40% more than B. How much percent is B less than A?
- Increase by 25% then decrease by 20%. Find net change.
- What is 12.5% of 720?
- What is 37.5% of 800?
- Convert 87.5% into fraction.
- Convert 7/8 into percentage.