Percentage, General Mathematics

Question: Samir spends `40%` of his salary on food articles and one third of the remaining on transport. If he saves Rs. `450` per month which is half of the balance after spending on food items and transport, what is his monthly salary ?
A
`Rs. 4500`

B
`Rs. 2250`

C
`Rs. 1125`

D
`Rs. 2500`

Note: Money spent on food artiles `= 40% 0f x` `= 40/(100) x` `= (2x)/5` Balance `= (x - (2x)/(5))` `= (3x)/5` Money spent on transport `= 1/3 xx (3x)/5` `= x/5` Balance now `= ((3x)/5 - x/(5))` `(2x)/5` `:. 1/2 xx (2x)/5` `= 450 ⇒ x` `= (450 xx 5)` `= 2250`
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Question: Kamal has some apples. He sold `40%` more than he ate. If he sold `70` apples, how many did he eat ?
A
`50`

B
`90`

C
`18`

D
`42`

Note: Suppose he ate x apples. Then, apples sold `= 140% of x` `= (140/100 xx x)` `= (7x)/5` `(7x)/5` `= 70 ⇒ x ` `= 70 xx 5/7` `= 50`
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Question: `5/9` part of the population in a village are males. If `30%` of the males are married, the percentage of unmarried females in the total population is :
A
`70%`

B
`40%`

C
`27 7/9%`

D
`20%`

Note: Let, total population `= x, Males` `= 5/(9) x.` Married males `= 30% of 5/(9) x` `= 30/100 xx 5/(9) x` `= x/6. Married females `= x/6. Total females `= (x - 5/(9) x)` `= (4x)/9` Unmarried percentage `= ((4x)/9 - x/6)` `= (5x)/18` :. Required percentage `= ((5x)/18 xx 1/x xx 100)%` `= 27 7/9%`
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Question: In an examination `1100` boys and `900` girls appeared. `50%` of the boys and `40%` of the girls passed the examination. The percentage of candidates failed is :
A
`45`

B
`45.5`

C
`54.5`

D
`59.2`

Note: Number of failures `= (50% of 1100 + 60% of 900)` `= (50/100 xx 1100 + 60/100 xx 900)` `= 1090.` Required percentage `= (1090/2000 xx 100)%` `= 54.5%`
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Question: A school has only three classes which contain `40, 50` and `60` students respectively. The pass percentage of the school is :
A
`13 1/3`

B
`15`

C
`20`

D
`16 2/3`

Note: Number of passed candidates `= (10/100 xx 40 + 20/100 xx 50 + 10/100 xx 60)` `= (4 + 10 + 6)` `= 20` Pass percentage `= 20/((40 + 50 + 60)) xx 100` `= (20/150 xx 100)%` `13 1/3 %`
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Question: `30%` of A ,s salary is equal to `20%` of `3/5 th` of B's salary. If B's salary is Rs. `2400,` what is A' s salary ?
A
`Rs. 1880`

B
`Rs. 1000`

C
`Rs. 960`

D
`Rs. 2160`

Note: `30% A` `= 20% of 3/5 B ⇒ (30A)/100` `= 20/100 xx 3/5 B` `:. A = 20/100 xx 3/5 xx 100/30 B` `= 2/5 B` `= (2/5 xx 2400)` `= 960`
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Question: Alekh secured `50%` marks in Hindi, `605` in English and `70%` in Maths as well as in Science. What were his total marks if the maximum marks obtainable in each of these `4` subjects was `50 ?`
A
`125`

B
`120`

C
`250`

D
`150`

Note: Total marks `= 50% of 50 + 60% of 50 + 70% of 50 + 70% of 50` `= (50/100 xx 50 + 60/100 xx 50 + 70/100 xx 50)` `= (25 + 30 35 + 35)` `= 125`
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Question: If `x%` of a is the same as `y%` of b, then `z%` of b is
A
`(yz)/x% f a`

B
`(xy)/z% of a`

C
`(xz)/y % of a`

D
None of these

Note: `x% of a` `= y% of b ⇒ x/100 a` `= y/100 b ⇒ b` `= (x/100 xx 100/y) a` `= (x/y) a` `:. z% of b` `= (z% of x/y) a` `= ((xz)/(y xx 100)) a` `= ((xz)/y)% of a.`
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Question: In a city, `35%` of the population is composed of migrants,` 20%` of whom are from rural areas. Of the local population, `48%` is female while this figure for rural and urban migrants is `30%` and `40%` respectively. If the total population of the city is `728400,` what is its female population ?
A
`324138`

B
`349680`

C
`509940`

D
None

Note: Migrants`= 35% of 728400` `= 35/100 xx 728400` `= 254940`. Local population `= (728400 - 254940)` `= 473460` Rural population Urban population `= (254940 - 94692)` `= 160248` :. Female population `= 48% of 473460 + 30% of 94692 + 40% of 160248` `= (48/100 xx 473460 + 30/100 xx 94692 + 40/100 xx 160248)` `= 227260.8 + 28407.6 + 64099.2` `= 896660.
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Question: A's marks in Biology are `20` less than `25%` of the total marks obtained by him in Biology, Maths and Drawing. If his marks in Drawing be `50` what are his marks in Maths ?
A
`40`

B
`45`

C
`50`

D
Can't be determined

Note: Let B + M + D = x. Then, `B = (25% of x - 20)` `= (25/100 x - 20)` `= (x/4 - 20) & d = 50` `:. x/4 - 20 + M + 50` `= x or M = ((3x)/4 - 30)` So, marks in Maths cannot be determined
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Question: Samir spends `40%` of his salary on food articles and one third of the remaining on transport. If he saves Rs. `450` per month which is half of the balance after spending on food items and transport, what is his monthly salary ?

Question: Kamal has some apples. He sold `40%` more than he ate. If he sold `70` apples, how many did he eat ?

Question: `5/9` part of the population in a village are males. If `30%` of the males are married, the percentage of unmarried females in the total population is :

Question: In an examination `1100` boys and `900` girls appeared. `50%` of the boys and `40%` of the girls passed the examination. The percentage of candidates failed is :

Question: A school has only three classes which contain `40, 50` and `60` students respectively. The pass percentage of the school is :

Question: `30%` of A ,s salary is equal to `20%` of `3/5 th` of B's salary. If B's salary is Rs. `2400,` what is A' s salary ?

Question: Alekh secured `50%` marks in Hindi, `605` in English and `70%` in Maths as well as in Science. What were his total marks if the maximum marks obtainable in each of these `4` subjects was `50 ?`

Question: If `x%` of a is the same as `y%` of b, then `z%` of b is

Question: A's marks in Biology are `20` less than `25%` of the total marks obtained by him in Biology, Maths and Drawing. If his marks in Drawing be `50` what are his marks in Maths ?