Percentage Practice Question and Answer
8 Q: A seller uses 920 gm in place of one kg to sell his goods. When he sells his articles at 15% gain on cost price, the actual percentage of profit is :
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Answer : 3. "25"
Q: The value of a machine depreciates at the rate of 10% per annum. It was purchased 3 years ago. If its present value is Rs.53071.20, the purchase price of the machine was:
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6024e9e6835ee1737390482b- 1Rs.72800true
- 2Rs.69680false
- 3Rs.84560false
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Answer : 1. "Rs.72800"
Q: A boy scored 125 marks and 140 marks in the first test and the second test respectively. If the maximum mark in each test is 150, then the percentage increase in his performance is ___________.
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638f3e8bd319b37ca182cc82- 15%false
- 215%false
- 325%false
- 410%true
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Answer : 4. "10%"
Q: A student multiplies a number by 5/3 instead of 3/5. What is the percentage error in the calculation?
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60b70f6f2f692872ec8cf904- 144 %false
- 234 %false
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Answer : 4. "64 %"
Q: The population of a city in the year 2020 was 2,00,000. The rate of growth of population is 8% per annum. Find the population of that city in the year 2022.
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642822c87ac9a186e4e061e7- 12,29,484false
- 22,33,280true
- 32,21,785false
- 42,12,890false
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Answer : 2. "2,33,280"
Q: If the length of a rectangle is increased by 10% and the area is unchanged, then how much percent does the breadth decrease?
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60237f7ead295556282decb7- 1true
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Answer : 1. "
Q: If the population of a town is 12.000 and the population increases at the rate of 10% per annum, then find the population. after 3 years.
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6426e27c72ca731a990e28e2- 115,972true
- 212,200false
- 311,200false
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Answer : 1. "15,972"
Explanation :
To find the population after 3 years given that it increases at a rate of 10% per annum, you can use the formula for exponential growth:
๐=๐0ร(1+๐)๐P=P0ร(1+r)n
Where:
- ๐P = Population after ๐n years
- ๐0P0 = Initial population
- ๐r = Rate of increase (in decimal form)
- ๐n = Number of years
Given:
- ๐0=12,000P0=12,000 (Initial population)
- ๐=0.10r=0.10 (10% increase per annum)
- ๐=3n=3 (Number of years)
Substitute these values into the formula:
๐=12,000ร(1+0.10)3P=12,000ร(1+0.10)3
๐=12,000ร(1.10)3P=12,000ร(1.10)3
๐=12,000ร(1.331)P=12,000ร(1.331)
๐=15,972P=15,972
So, the population after 3 years would be approximately 15,972.
Q: The price of sugar increases by 15%. By what percentage should the consumption of sugar be decreased so that the expenditure on the purchase of sugar remains the same? [Give your answer correct to 2 decimal places.]
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643d140332185cce373eec85- 111.11%false
- 212.5%false
- 314.16%false
- 413.04%true
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Answer : 4. "13.04%"
Explanation :
To solve this problem, let's denote:
- Initial price of sugar = P
- Initial quantity consumed = Q
- Initial expenditure = PQ
After the price increases by 15%, the new price becomes 1.15P.
To keep the expenditure constant, the new quantity consumed (let's call it Q') can be calculated using the formula:
New expenditure = New price ร New quantity
Setting the new expenditure equal to the initial expenditure:
PQ = (1.15P) * Q'
Now, solve for Q':
Q' = PQ / (1.15P)
Simplify:
Q' = Q / 1.15
Now, let's find the percentage decrease in consumption:
Percentage decrease = [(Q - Q') / Q] * 100
Substituting the value of Q':
Percentage decrease = [(Q - (Q / 1.15)) / Q] * 100
Percentage decrease = [(Q * (1 - 1/1.15)) / Q] * 100
Percentage decrease โ [(1 - 0.8696) * 100] โ 13.04%
Therefore, the consumption of sugar should be decreased by approximately 13.04% to keep the expenditure on the purchase of sugar the same after a 15% increase in price.