PlacementPrepThe price of an item is first increased by 50% and then decreased by 25%. What is the net change in price?
Solution
Net change = a − b − ab/100 = 50 − 25 − (50×25)/100 = 12.5%.
Answer: (B) 12.5% increase
Quantitative Aptitude · Arithmetic
Percentages: placement practice questions
30 moderate questions in the pattern of campus placement tests. Pick an option to check your answer, then open the step-by-step solution.
In an election between two candidates, 25% of the 5000 votes were invalid. The winner got 55% of the valid votes. By how many votes did the winner win?
Solution
Valid votes = 75% of 5000 = 3750.
Winner = 55% of 3750 = 2062; loser = 1688.
Margin = 2062 − 1688 = 374.
Answer: (D) 374
A person spends 30% of his salary on rent and 20% of the remainder on food. If his salary is Rs. 36,000, how much is left?
Solution
After rent: 70% of 36000 = 25200.
After food: 80% of 25200 = 20160.
Answer: (B) Rs. 20,160
The population of a town is 40000. It grows by 20% every year. What will it be after 2 years?
Solution
After 2 years = 40000 × (1 + 20/100)² = 40000 × 36/25 = 57600.
Answer: (C) 57,600
If the price of sugar rises by 20%, by what percentage must a family reduce consumption to keep the expenditure the same?
Solution
Reduction = r/(100 + r) × 100 = 20/120 × 100 = 16 2/3%.
Answer: (C) 16 2/3%
The price of an item is first increased by 30% and then decreased by 25%. What is the net change in price?
Solution
Net change = a − b − ab/100 = 30 − 25 − (30×25)/100 = -2.5%.
Answer: (B) 2.5% decrease
What is 25% of 45% of 240?
Solution
45% of 240 = 108.
25% of 108 = 27.
Answer: (B) 27
In an election between two candidates, 20% of the 8000 votes were invalid. The winner got 55% of the valid votes. By how many votes did the winner win?
Solution
Valid votes = 80% of 8000 = 6400.
Winner = 55% of 6400 = 3520; loser = 2880.
Margin = 3520 − 2880 = 640.
Answer: (D) 640
A person spends 40% of his salary on rent and 25% of the remainder on food. If his salary is Rs. 60,000, how much is left?
Solution
After rent: 60% of 60000 = 36000.
After food: 75% of 36000 = 27000.
Answer: (B) Rs. 27,000
The price of an item is first increased by 40% and then decreased by 10%. What is the net change in price?
Solution
Net change = a − b − ab/100 = 40 − 10 − (40×10)/100 = 26%.
Answer: (B) 26% increase
In an election between two candidates, 25% of the 8000 votes were invalid. The winner got 70% of the valid votes. By how many votes did the winner win?
Solution
Valid votes = 75% of 8000 = 6000.
Winner = 70% of 6000 = 4200; loser = 1800.
Margin = 4200 − 1800 = 2400.
Answer: (C) 2400
A person spends 25% of his salary on rent and 40% of the remainder on food. If his salary is Rs. 30,000, how much is left?
Solution
After rent: 75% of 30000 = 22500.
After food: 60% of 22500 = 13500.
Answer: (A) Rs. 13,500
The population of a town is 25000. It grows by 10% every year. What will it be after 2 years?
Solution
After 2 years = 25000 × (1 + 10/100)² = 25000 × 121/100 = 30250.
Answer: (C) 30,250
The price of an item is first increased by 10% and then decreased by 20%. What is the net change in price?
Solution
Net change = a − b − ab/100 = 10 − 20 − (10×20)/100 = -12%.
Answer: (A) 12% decrease
What is 50% of 15% of 1200?
Solution
15% of 1200 = 180.
50% of 180 = 90.
Answer: (A) 90
A person spends 30% of his salary on rent and 20% of the remainder on food. If his salary is Rs. 40,000, how much is left?
Solution
After rent: 70% of 40000 = 28000.
After food: 80% of 28000 = 22400.
Answer: (D) Rs. 22,400
The population of a town is 12000. It grows by 20% every year. What will it be after 2 years?
Solution
After 2 years = 12000 × (1 + 20/100)² = 12000 × 36/25 = 17280.
Answer: (D) 17,280
If the price of sugar rises by 50%, by what percentage must a family reduce consumption to keep the expenditure the same?
Solution
Reduction = r/(100 + r) × 100 = 50/150 × 100 = 33 1/3%.
Answer: (A) 33 1/3%
The price of an item is first increased by 40% and then decreased by 25%. What is the net change in price?
Solution
Net change = a − b − ab/100 = 40 − 25 − (40×25)/100 = 5%.
Answer: (A) 5% increase
What is 25% of 84% of 1200?
Solution
84% of 1200 = 1008.
25% of 1008 = 252.
Answer: (A) 252
In an election between two candidates, 25% of the 5000 votes were invalid. The winner got 60% of the valid votes. By how many votes did the winner win?
Solution
Valid votes = 75% of 5000 = 3750.
Winner = 60% of 3750 = 2250; loser = 1500.
Margin = 2250 − 1500 = 750.
Answer: (C) 750
A person spends 30% of his salary on rent and 20% of the remainder on food. If his salary is Rs. 60,000, how much is left?
Solution
After rent: 70% of 60000 = 42000.
After food: 80% of 42000 = 33600.
Answer: (B) Rs. 33,600
If the price of sugar rises by 25%, by what percentage must a family reduce consumption to keep the expenditure the same?
Solution
Reduction = r/(100 + r) × 100 = 25/125 × 100 = 20%.
Answer: (C) 20%
The price of an item is first increased by 25% and then decreased by 10%. What is the net change in price?
Solution
Net change = a − b − ab/100 = 25 − 10 − (25×10)/100 = 12.5%.
Answer: (D) 12.5% increase
In an election between two candidates, 20% of the 4000 votes were invalid. The winner got 60% of the valid votes. By how many votes did the winner win?
Solution
Valid votes = 80% of 4000 = 3200.
Winner = 60% of 3200 = 1920; loser = 1280.
Margin = 1920 − 1280 = 640.
Answer: (B) 640
A person spends 10% of his salary on rent and 20% of the remainder on food. If his salary is Rs. 24,000, how much is left?
Solution
After rent: 90% of 24000 = 21600.
After food: 80% of 21600 = 17280.
Answer: (D) Rs. 17,280
In an election between two candidates, 25% of the 4000 votes were invalid. The winner got 55% of the valid votes. By how many votes did the winner win?
Solution
Valid votes = 75% of 4000 = 3000.
Winner = 55% of 3000 = 1650; loser = 1350.
Margin = 1650 − 1350 = 300.
Answer: (D) 300
The population of a town is 10000. It grows by 20% every year. What will it be after 2 years?
Solution
After 2 years = 10000 × (1 + 20/100)² = 10000 × 36/25 = 14400.
Answer: (C) 14,400
What is 20% of 35% of 1200?
Solution
35% of 1200 = 420.
20% of 420 = 84.
Answer: (C) 84
The population of a town is 40000. It grows by 10% every year. What will it be after 2 years?
Solution
After 2 years = 40000 × (1 + 10/100)² = 40000 × 121/100 = 48400.
Answer: (D) 48,400
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