Study Material — 14 PYQs (2020–2020) · Concept Notes · Shortcuts
SBI Clerk Percentage Change is a frequently tested subtopic — 14 previous year questions from 2020–2020 papers are included below with concept notes, key rules and shortcut tricks.
14 questions from actual SBI Clerk papers · all shown free · click option to reveal solution
Exam Q 12020Previous Year Pattern
A student's marks increased from 60 to 75. What is the percentage increase in marks?
Exam Q 22020Previous Year Pattern
The price of a shirt increased from ₹400 to ₹500. What is the percentage increase in price?
Exam Q 32020Previous Year Pattern
A company's revenue increased from ₹2,00,000 to ₹2,50,000. What is the percentage increase in revenue?
Exam Q 42020Previous Year Pattern
The number of employees in a factory decreased from 1,200 to 1,000. What is the percentage decrease in the number of employees?
Exam Q 52020Previous Year Pattern
A shopkeeper reduced the price of a book from ₹800 to ₹600. What is the percentage decrease?
Exam Q 62020Previous Year Pattern
The population of a town decreased from 50,000 to 40,000. What is the percentage decrease in population?
Exam Q 72020Previous Year Pattern
A shopkeeper increases the cost price of an item by 40% to set the marked price. He then offers a discount of 25% on the marked price. What is his profit or loss percentage?
Exam Q 82020Previous Year Pattern
The price of a commodity increases by 25% in the first year and then decreases by 20% in the second year. What is the net percentage change in price over the two years?
Exam Q 92020Previous Year Pattern
A company's revenue was ₹50 lakhs in 2022. It increased to ₹65 lakhs in 2023. If the revenue increases by the same percentage in 2024, what will be the revenue in 2024?
Exam Q 102020Previous Year Pattern
The price of petrol decreases by 10% and then increases by 10%. What is the net percentage change in price?
Exam Q 112020Previous Year Pattern
The population of a town increases by 15% in the first year. In the second year, it decreases by 10%. In the third year, it increases by 20%. What is the net percentage change in population after three years?
Exam Q 122020Previous Year Pattern
The price of a commodity was reduced by 15%, then increased by 20%, and finally reduced by 10%. If the final price is ₹918, what was the original price?
Exam Q 132020Previous Year Pattern
A student's marks increased by 20% in the first exam and then decreased by 25% in the second exam compared to the first exam. If the marks in the second exam are 360, what were the original marks?
Exam Q 142020Previous Year Pattern
A company's revenue increased by 30% in Year 1 and decreased by 25% in Year 2. If the revenue at the end of Year 2 is ₹1,17,000, what was the initial revenue?
Concept Notes
Percentage Change— Rules & Concept
Core ConceptRead this first — the foundation of the topic
Percentage change is the difference between the original value and the new value, expressed as a percentage of the original value. This concept appears in almost every SSC CGL paper and forms the backbone of profit-loss, simple interest, and data interpretation questions. Core Concept: When any quantity increases or decreases, we calculate the percentage change to measure the rate of change. For example, if your salary increases from Rs 20,000 to Rs 25,000, the percentage increase is 25%.
Formula BlockMemorise — at least one formula appears in every paper
Block:
• Percentage Increase = [(New Value - Original Value) / Original Value] × 100
• Percentage Decrease = [(Original Value - New Value) / Original Value] × 100
• New Value after x% increase = Original Value × (100 + x)/100
• New Value after x% decrease = Original Value × (100 - x)/100
• Successive percentage changes: If a value changes by a% then b%, final change = [a + b + (ab/100)]%
Exam PatternsWhat examiners ask — read before attempting PYQs
SSC loves asking percentage change in population growth, salary hikes, price fluctuations, and successive discounts. Questions often involve finding original values when final values and percentage changes are given.
ShortcutsUse these to save 30–60 seconds per question
1
Two successive increases of x% = (x + x + x²/100)% total increase
2
One increase of x% followed by decrease of x% = (x²/100)% net decrease
3
25% increase means multiply by 1.25
4
20% decrease means multiply by 0.8
5
12.5% increase means multiply by 9/8
Worked ExampleSolve this step-by-step before moving on
1
Step 1
Identify original value = 50,000, new value = 65,000
2
Step 2
Find increase = 65,000 - 50,000 = 15,000
3
Step 3
Apply formula = (15,000/50,000) × 100 = 30%
Answer: 30% increase
Worked Example 2:
A number is first increased by 20% and then decreased by 15%. Find the overall percentage change.
1
Step 1
Let original number = 100 (always take 100 for easier calculation)
2
Step 2
After 20% increase = 100 × 1.2 = 120
3
Step 3
After 15% decrease = 120 × 0.85 = 102
4
Step 4
Overall change = 102 - 100 = 2
5
Step 5
Percentage change = 2% increase
Alternative: Using formula = 20 + (-15) + (20×(-15)/100) = 20 - 15 - 3 = 2% increase
Shortcut Trick #3: Percentage to fraction conversions:
• 12.5% = 1/8, 16.67% = 1/6, 33.33% = 1/3, 66.67% = 2/3
• These help in quick mental calculations during exams.
Exam TrapsCommon mistakes students make — avoid these
#1: Students often confuse which value to use as base. Remember: percentage change is always calculated on the ORIGINAL value, not the new value. If price changes from Rs 100 to Rs 120, the base is Rs 100, not Rs 120.
Many students calculate (20/120) × 100 instead of (20/100) × 100, leading to wrong answers.
Exam Strategy: Practice reverse calculations where you find original values from final values and percentage changes. SSC frequently tests this concept in tricky word problems involving multiple successive changes.
Key Points to Remember
Percentage change = [(New Value - Original Value) / Original Value] × 100
Always use original value as denominator, never the new value
Successive changes formula: a + b + (ab/100) for changes of a% and b%