SSC MTS Percentage Change ā Study Material, 5 PYQs & Practice MCQs | ZestExam
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SSC MTS Percentage Change
Study Material ā 5 PYQs (2020ā2020) Ā· Concept Notes Ā· Shortcuts
SSC MTS Percentage Change is a frequently tested subtopic ā 5 previous year questions from 2020ā2020 papers are included below with concept notes, key rules and shortcut tricks.
5 questions from actual SSC MTS papers Ā· all shown free Ā· click option to reveal solution
Exam Q 12020Previous Year Pattern
A population decreased by 20% in Year 1. To return to its original size by the end of Year 2, by what percentage must it increase in Year 2?
Exam Q 22020Previous Year Pattern
A company's revenue increased by 40% in Year 1, then decreased by 30% in Year 2. If the revenue at the end of Year 2 was ā¹98 lakhs, what was the initial revenue?
The price of petrol increased by 15% in the first quarter and by 12% in the second quarter. By what percentage did the price increase over the two quarters combined?
Exam Q 42020Previous Year Pattern
A student's marks increased from 320 to 400. Later, the marks were recalculated and decreased by 10%. What is the net percentage change from the original marks of 320?
Exam Q 52020Previous Year Pattern
A product's cost price is ā¹500. The shopkeeper marks it up by 60%, then offers a discount of 25% on the marked price. What is the profit percentage?
Concept Notes
Percentage Changeā Rules & Concept
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Core Concept
Read this first ā 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%.
Key
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Formula Block
Memorise ā at least one formula appears in every paper
ā¢ Percentage Increase = [(New Value - Original Value) / Original Value] Ć 100
ā¢ Percentage Decrease = [(Original Value - New Value) / Original Value] Ć 100
ā¢ New Value after x% increase = Original Value Ć (100 + x)/100
ā¢ New Value after x% decrease = Original Value Ć (100 - x)/100
ā¢ Successive percentage changes: If a value changes by a% then b%, final change = [a + b + (ab/100)]%
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Exam Patterns
What examiners ask ā read before attempting PYQs
š”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) Ć 100 instead of (20/100) Ć 100, leading to wrong answers
šExam 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] Ć 100
Always use original value as denominator, never the new value
Successive changes formula: a + b + (ab/100) for changes of a% and b%
The population of a town decreased from 50,000 to 45,000. What is the percentage decrease in population?
Practice 2easy
A product's price was increased by 25% and then decreased by 20%. What is the net percentage change in price?
Practice 3easy
A shopkeeper reduced the price of a shirt from ā¹800 to ā¹600. What is the percentage decrease?
Practice 4easy
The price of a book increased from ā¹200 to ā¹250. What is the percentage increase in price?
Practice 5easy
A number increased by 20% gives 360. What is the original number?
Practice 6medium
A retailer increases the price of an item by 30% and then gives a discount of 30% on the new price. A customer claims he gets the item at the original price. Is the customer correct?
Practice 7medium
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?
Practice 8medium
A shopkeeper buys goods at ā¹800 per unit. He marks up the price by 40% but then offers a 25% discount on the marked price. What is the percentage profit or loss?
Practice 9medium
The value of a car depreciates by 15% in the first year and by 10% in the second year. If the car's value after two years is ā¹1,53,000, what was its original value?
Practice 10hard
A shopkeeper increases the price of an item by 25%, then due to poor sales, reduces the new price by 20%. If the final price is ā¹600, what was the original price?