Percentage
- A man donated 5% of his income to a charitable organisation and deposited 20% of the remainder in a bank. If he now has Rs. 1919 left, what is his income ?
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Let his income be Rs. N, then N - 5% of N - 20% of 95% of N = 1919
⇒ N - N/20 - (20 x 95 x N)/(100 x 100) = 1919Correct Option: B
Let his income be Rs. N, then N - 5% of N - 20% of 95% of N = 1919
⇒ N - N/20 - (20 x 95 x N)/(100 x 100) = 1919
⇒ N - N/20 - 19N/100 = 1919
⇒ 100N - 5N - 9N = 191900
∴ N = 191900 / 76 = 2525
- Rakesh credits 15% of his salary in his fixed deposit account and spend 30% of the remaining amount on groceries. If the cash in hand is Rs. 2380, What is this salary ?
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Let salary be Rs. A, then A - 15 % of A - 30% of 85% of A = 2380
⇒ A - 15A/100 - (30 x 85 x A)/(100 x 100) = 2380
⇒ 200A - 30A - 51A = 2380 x 200Correct Option: B
Let salary be Rs. A, then A - 15 % of A - 30% of 85% of A = 2380
⇒ A - 15A/100 - (30 x 85 x A)/(100 x 100) = 2380
⇒ 200A - 30A - 51A = 2380 x 200
⇒ 119A = 2380 x 200
∴ A = (2380 x 200)/199 = 4000
- A city has a population of 300000 out of which 180000 are males. 50% of the population is literate. If 70% of the males are literate, the number of literate females is
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Total population = 300000
Total number of males = 180000
Total Literates = 50% of total population = 150000
Number of literate males = 70% of males = 126000Correct Option: A
Total population = 300000
Total number of males = 180000
Total Literates = 50% of total population = 150000
Number of literate males = 70% of males = 126000
∴ Number of literate females = 150000 - 126000 = 24000
- If the price of petrol is increased by 20%, by what percentage should the consumption be decreased by the consumer, if the expenditure on petrol remains unchanged ?
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Required decrease in consumption = [a/(100 + a)] x 100%
Where a = 20.Correct Option: A
Required decrease in consumption = [a/(100 + a)] x 100%
= [20/(100 + 20)] x 100%
= (20/120) x 100%
= 162/3%
- The population of a city increases at the rate of 5% per annum. There is additional annual increases of 5% due to influx of job seekers. The percent increase in population after 3 yr, is ?
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Total rate of increase in population per annum = 10%
Initially, let the population be 1000
population after 3 yr = 1000(1 + 10/100)3
= (1000 x 11/10 x 11/10 x 11/10) = 1331Correct Option: A
Total rate of increase in population per annum = 10%
Initially, let the population be 1000
population after 3 yr = 1000(1 + 10/100)3
= (1000 x 11/10 x 11/10 x 11/10) = 1331
∴ Increase in percentage = [(1331 - 1000)/1000] x 100%
= (331/1000) x 100%
= 33.1%
