Percentage, General Mathematics

Question: An increase of Rs. `60` in the monthly salary of Madam made it `50%` of the monthly salary of kamal. What is Madam' s present monthly salary ?
A
Rs. 180`

B
`Rs. 240`

C
`Rs. 300`

D
Data inadequate

Note: `M + 60` `= 50% of K.` Clearly, M cannot be determined
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Question: From a container having pure milk,` 20%` is replaced by water and the process is repeated thrice. At the end of the third operation, the milk is :
A
`40% pure`

B
`50% pure`

C
`51.2% pure`

D
`58.8% pure`

Note: Let total quantity of original milk `= 1000 gm.` Milk after first operation `= 80% of 1000` `= 800 gm.` Milk after second operation `= 80% of 800` `= 640 gm.` Milk after third operation `= 80% of 640` `= 512 gm.` :. Strength of final mixture `= 51`2%`
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Question: A man bought a house for Rs.` 5` lakhs and rents it. He puts `12 1/2%` of each month's rent aside for repairs, pays Rs.`1660` as annual taxes and realises `10%` on his investment thereafter. The monthly rent of the house is :
A
`Rs. 5000`

B
`Rs. 4920`

C
`Rs. 2500`

D
`Rs. 2460`

Note: Suppose monthly rent = Rs. x Then, `12x - (25)/2% of 12x - 1660` `⇒ 10% of 500000` `⇒ 12x - (25)/200 xx 12x - 1660` `⇒ 500000` `⇒ (21x)/2` `= 51660 or x` `= (51660 xx 2/21)` `= 4920.`
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Question: In a public school, `1/5 th` of the girls and `1/4 th` of boys are under `12` years of age. If the total strength of the school is `1000` and number of girls is `2/5 th` of the total, what part of the total strength of the school is accounted for by those which are `12` years or more of age ?
A
`23%`

B
`45%`

C
`55%`

D
`77%`

Note: Girls` = (2/5 xx 1000)` `= 400,` Boys `= 600` Under `12` years `= (1/5 xx 400 + 1/4 xx 600)` `= 230` Above `12` years `= (1000 - 230)` `= 770.` Required percentage `= (770/1000 xx 100)%` `= 77%`.
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Question: The salaries of A and B together amount to Rs.`2000.` A spends `95%` of his salary and B,` 85%` of his. If now, their saving are the same, what is A's salary ?
A
`Rs. 1500`

B
`Rs. 1250`

C
`Rs. 750`

D
`Rs. 1600`

Note: Let A's salary = x. Then, B's` = (2000 - x)` `5% of A` `= 15% of B, i. e. 5/100 x` `= 15/100 (2000 - x) or x` `= 1500.`
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Question: A debtor can pay `87` paise in the rupee, but if his creditors would take `20%` of his debts he could pay them and have Rs. `42` left. His debts and assets respectively are
A
`Rs. 600, Rs. 522`

B
`Rs. 500, Rs. 521`

C
`Rs. 400, Rs. 520`

D
`Rs. 1000, Rs. 525`

Note: Let the total debt = x. Asset with him `= 87/(100) x.` After paying `20%` of the debt, he is left with `80%` of the debt plus Rs.` 42.` `:. 80% of x + 42` `= 87/(100) x or 87/(100) x - 80/(100) x` `= 42 or x = 600.` :. Debt `= Rs. 600 &` Assets `= 87/100 xx 600` `= Rs. 522.`
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Question: `300` grams of sugar solution has `40%` sugar in it.How much sugar should be added to make it `50%` in the solution ?
A
`10 gms`

B
`40 gms`

C
`60 gms`

D
`80 gms`

Note: Sugar`= (40/100 xx 300) gms` `= 120 gms, water`= 180 gms` Let x gm sugar may be added. Then,(120 + x)/(300 + x) xx 100` `= 50 ⇒ 240 + 2x` `= 300 + x ⇒ x = 60.`
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Question: The quantity of water (in ml) needed to reduce `9` ml shaving lotion containing `50%` alcohol to a lotion containing `30%`alcohol, is :
A
`4`

B
`5`

C
`6`

D
`7`

Note: Alcohol in `9` ml `= (50/100 xx 9) ml` `= 4.5 ml`, water` = 4.5 ml.` Let the water to be added be x ml. Then,`(4.5)/(9 + x) xx 100` `= 30 ⇒ 450` `= 270 + 30x ⇒ x = 6 ml`
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Question: To a sugar solution of `3` litres containing `40%` sugar, one litre of water is added. The percentage of sugar in the new solution is :
A
`13 1/3%`

B
`15%`

C
`30%`

D
`33%`

Note: Sugar` = (40/100 xx 3) litres` `= 1.2 litres,` water`= 1.8 litres` New percentage`= (1.2/4 xx 100)%` `= 30%`
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Question: The price of an article is cut by `20%`. To restore it the former value, the new price must be increased by :
A
`20%`

B
`25%`

C
`16 2/3%`

D
`24%`

Note: Let original price`= 100`. New price`= 80` Increase on`80 = 20` Increase on`100 = (20/80 xx 100)%` `= 25%`.
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Question: An increase of Rs. `60` in the monthly salary of Madam made it `50%` of the monthly salary of kamal. What is Madam' s present monthly salary ?

Question: From a container having pure milk,` 20%` is replaced by water and the process is repeated thrice. At the end of the third operation, the milk is :

Question: A man bought a house for Rs.` 5` lakhs and rents it. He puts `12 1/2%` of each month's rent aside for repairs, pays Rs.`1660` as annual taxes and realises `10%` on his investment thereafter. The monthly rent of the house is :

Question: The salaries of A and B together amount to Rs.`2000.` A spends `95%` of his salary and B,` 85%` of his. If now, their saving are the same, what is A's salary ?

Question: A debtor can pay `87` paise in the rupee, but if his creditors would take `20%` of his debts he could pay them and have Rs. `42` left. His debts and assets respectively are

Question: `300` grams of sugar solution has `40%` sugar in it.How much sugar should be added to make it `50%` in the solution ?

Question: The quantity of water (in ml) needed to reduce `9` ml shaving lotion containing `50%` alcohol to a lotion containing `30%`alcohol, is :

Question: To a sugar solution of `3` litres containing `40%` sugar, one litre of water is added. The percentage of sugar in the new solution is :

Question: The price of an article is cut by `20%`. To restore it the former value, the new price must be increased by :