Question 1

A company's revenue was ₹50 lakhs last year. This year it increased to ₹65 lakhs. Next year, the revenue is projected to decrease by 10% from this year's figure. What will be the revenue next year?

Accepted Answer

Step 1: This year's revenue = ₹65 lakhs. Step 2: Next year's revenue = 65 - (10% of 65) = 65 - 6.5 = ₹58.5 lakhs. Step 3: Alternatively, next year's revenue = 65 × 0.90 = ₹58.5 lakhs.

Question 2

The price of petrol decreases by 15% one month and then increases by 20% the next month. If the original price was ₹80 per litre, what is the final price?

Accepted Answer

Step 1: Original price = ₹80. Step 2: After 15% decrease: Price = 80 - (15% of 80) = 80 - 12 = ₹68. Step 3: After 20% increase on ₹68: Price = 68 + (20% of 68) = 68 + 13.6 = ₹81.6. Step 4: Final price = ₹81.6 per litre.

Question 3

A student's marks increased from 60 to 75. What is the percentage increase in marks?

Accepted Answer

Step 1: Initial marks = 60, Final marks = 75. Step 2: Increase = 75 - 60 = 15. Step 3: Percentage increase = (Increase / Initial value) × 100 = (15 / 60) × 100 = 25%.

Question 4

The population of a town increases by 10% in the first year. In the second year, it decreases by 5%. In the third year, it increases by 20%. What is the net percentage change in population over three years?

Accepted Answer

Step 1: Let initial population = 100. Step 2: After year 1 (+10%): Population = 100 × 1.10 = 110. Step 3: After year 2 (-5%): Population = 110 × 0.95 = 104.5. Step 4: After year 3 (+20%): Population = 104.5 × 1.20 = 125.4. Step 5: Net change = 125.4 - 100 = 25.4. Step 6: Net percentage change = 25.4%.

Question 5

The population of a town increases by 30% in the first year and decreases by 25% in the second year. If the population after 2 years is 117,000, what was the initial population?

Accepted Answer

Step 1: Let initial population = P. After year 1: P × 1.30. Step 2: After year 2: P × 1.30 × 0.75 = P × 0.975. Step 3: P × 0.975 = 117,000. Step 4: P = 117,000 ÷ 0.975 = 120,000.

Question 6

A shopkeeper increases the price of an item by 25%, then due to poor sales, he reduces the new price by 20%. If the final price is ₹600, what was the original price?

Accepted Answer

Step 1: Let original price = P. After 25% increase, price = 1.25P. Step 2: After 20% reduction on 1.25P, price = 1.25P × 0.80 = P. Step 3: So P = 600. Therefore, original price is ₹600.

Question 7

A quantity increases by 25% and then decreases by 25%. The result is compared to the original quantity. What is the net percentage change?

Accepted Answer

Step 1: Let original quantity = Q. Step 2: After +25%: 1.25Q. Step 3: After −25%: 1.25Q × 0.75 = 0.9375Q. Step 4: Net change = 0.9375Q − Q = −0.0625Q. Step 5: Percentage change = (−0.0625Q / Q) × 100 = −6.25%.

Question 8

A student's marks decreased from 80 to 60. What is the percentage decrease in marks?

Accepted Answer

Step 1: Calculate the decrease = 80 - 60 = 20 marks. Step 2: Apply percentage decrease formula: (Decrease / Original) × 100 = (20 / 80) × 100 = 25%. Therefore, the percentage decrease is 25%.

Question 9

The price of a shirt increased from ₹400 to ₹500. What is the percentage increase in price?

Accepted Answer

Step 1: Calculate the increase in price = 500 - 400 = ₹100. Step 2: Apply percentage change formula: (Change / Original) × 100 = (100 / 400) × 100 = 25%. Therefore, the percentage increase is 25%.

Question 10

The population of a town was 50,000 in 2020 and became 60,000 in 2021. What is the percentage growth in population?

Accepted Answer

Step 1: Calculate the increase in population = 60,000 - 50,000 = 10,000. Step 2: Apply percentage change formula: (Increase / Original Population) × 100 = (10,000 / 50,000) × 100 = 20%. Therefore, the percentage growth is 20%.

Question 11

A shopkeeper bought an item for ₹200 and sold it for ₹250. What is the percentage profit?

Accepted Answer

Step 1: Calculate profit = Selling Price - Cost Price = 250 - 200 = ₹50. Step 2: Apply profit percentage formula: (Profit / Cost Price) × 100 = (50 / 200) × 100 = 25%. Therefore, the percentage profit is 25%.

Question 12

A mobile phone's price was reduced from ₹15,000 to ₹12,000. What is the percentage discount offered?

Accepted Answer

Step 1: Calculate the discount amount = 15,000 - 12,000 = ₹3,000. Step 2: Apply discount percentage formula: (Discount / Original Price) × 100 = (3,000 / 15,000) × 100 = 20%. Therefore, the percentage discount is 20%.

Question 13

A worker's daily wage increased from ₹500 to ₹600. What is the percentage increase in the daily wage?

Accepted Answer

Step 1: Calculate the wage increase = 600 - 500 = ₹100. Step 2: Apply percentage increase formula: (Increase / Original Wage) × 100 = (100 / 500) × 100 = 20%. Therefore, the percentage increase in daily wage is 20%.

Question 14

A shopkeeper buys an item for ₹400. He marks it up by 50% and then offers a discount of 30% on the marked price. What is his profit or loss percentage?

Accepted Answer

Step 1: Cost Price (CP) = ₹400. Step 2: Marked Price (MP) = 400 + 50% of 400 = 400 + 200 = ₹600. Step 3: Selling Price (SP) = 600 - 30% of 600 = 600 - 180 = ₹420. Step 4: Profit = 420 - 400 = ₹20. Step 5: Profit% = (20/400) × 100 = 5%.

Question 15

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 the price over the two years?

Accepted Answer

Step 1: Let initial price = 100. After 25% increase: Price = 100 + 25 = 125. Step 2: After 20% decrease on 125: Price = 125 - (20% of 125) = 125 - 25 = 100. Step 3: Net change = 100 - 100 = 0. Therefore, net percentage change = 0%.

SSC GD Constable Percentage Change

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60-Second Revision — Percentage Change