Percentage - Exercise 12.2 | Mathematics (Maths) Class 8 PDF Download

 Page 1


      
  
  
  
  
  
      
       
         
     
      
Q u e s t i o n : 4
Find:
i
22% of 120
i i
25% of Rs 1000
i i i
25% of 10 kg
i v
16.5% of 5000 metre
v
135% of 80 cm
v i
2.5% of 10000 ml
S o l u t i o n :
( ) ( ) ( ) ( ) (
Page 2


      
  
  
  
  
  
      
       
         
     
      
Q u e s t i o n : 4
Find:
i
22% of 120
i i
25% of Rs 1000
i i i
25% of 10 kg
i v
16.5% of 5000 metre
v
135% of 80 cm
v i
2.5% of 10000 ml
S o l u t i o n :
( ) ( ) ( ) ( ) (
i 22 % of 120 =
22
100
×120 = 26. 4 ii 25 % of 1000 =
25
100
×1000 = 250 iii 25 % of 10 kg =
25
100
×10 kg =
25
10
kg =
5
2
kg = 2. 5 kg iv 16. 5 % of 5000 m =
16.5
100
×5000 m = 16. 5 ×50 m = 825 m
Q u e s t i o n : 5
Find the number a, if
i
8.4% of a is 42
i i
0.5% of a  is 3
i i i
1
2
%
of a is 50
i v
100% of a is 100
S o l u t i o n :
i 8. 4 % o f a is 42. i. e. , 
8.4
100
× a = 42 ? a =
42×100
8.4
? a = 500 ii 0. 5 % o f a is 3. i. e. , 
0.5
100
× a = 3 ? a =
3×100
0.5
? a = 600 iii 
1
2
% o f a is 50. i. e. , 
1
2
×
1
100
× a = 50 ? a = 50 ×200 ? a = 10000
Q u e s t i o n : 6
x is 5% of y, y is 24% of z. If x = 480, find the values of y and z.
S o l u t i o n :
Given: x =
5
100
y ? y =
100
5
x ? y = 20 xAlso, y =
24
100
z ? z =
100
24
yPutting x = 480 in the above equations, w e get: y = 20(480) = 9600 z =
100
24
×9600 = 40000
Q u e s t i o n : 7
A coolie deposits Rs 150 per month in his post office Savings Bank account. If this is 15% of his monthly income, find his monthly income.
S o l u t i o n :
Let his monthly income be Rs x . Then, 15 % o f x = 150 ?
15
100
x = 150 ? x =
150×100
15
= 1000 ? His monthly income is Rs 1000.
Q u e s t i o n : 8
Asha got 86.875% marks in the annual examination. If she got 695 marks, find the total number of marks of the examination.
S o l u t i o n :
Let x be the total number of marks of the examination. Then, 86. 875 % of x = 695 ?
86.875
100
x = 695 ? x =
695×100
86.875
= 800 ? The total number of marks of the examination is 800.
Q u e s t i o n : 9
Deepti went to school for 216 days in a full year. If her attendance is 90%, find the number of days on which the school was opened.
S o l u t i o n :
Let the school opened for x days in the given year. We have: 90 % o f x = 216 ?
90
100
x = 216 ? x =
216×100
90
= 240 ? The school opened for 240 days in the given year.
Q u e s t i o n : 1 0
A garden has 2000 trees. 12% of these are mango trees, 18% lemon and the rest are orange trees. Find the number of orange trees.
S o l u t i o n :
Let the number of orange trees be x. It is given that there are 2, 000 trees. While 12 % of them are mango trees, 18 % are lemon trees and the rest are orange trees. Now, (12 % o f 2000) +(
Q u e s t i o n : 1 1
Balanced diet should contain 12% of proteins, 25% of fats and 63% of carbohydrates. If a child needs 2600 calories in this food daily, find in calories the amount of each of these in his
daily food intake.
S o l u t i o n :
In a balanced diet of 2600 calories, 12 % is protein. ? Amount of protein in food intake = 12 % of 2600 =
12
100
×2600 = 312Similarly, a balanced diet contain s 25 % fats. ? Amount of fats
Q u e s t i o n : 1 2
A cricketer scored a total of 62 runs in 96 balls. He hit 3 sixes, 8 fours, 2 twos and 8 singles. What percentage of the total runs came in
i
Sixes
i i
fours
i i i
twos
i v
singles
S o l u t i o n :
i The cricketer hits 3 sixes. i. e. , 3 ×6 = 18 ? 
18
62
×100 = 29. 03 % ii The cricketer hits 8 fours. i. e. , 8 ×4 = 32 ? 
32
62
×100 = 51. 61 % iii The cricketer hits 2 twos. i. e. , 2 ×2 = 4 ? 
4
62
×100
Q u e s t i o n : 1 3
A cricketer hit 120 runs in 150 balls during a test match. 20% of the runs came in 6's, 30% in 4's, 25% in 2's and the rest in 1's. How many runs did he score in
i
6's
i i
4's
i i i
2's
i v
singles
What % of his shots were scoring ones?
S o l u t i o n :
i Let the cricketer score w runs in 6' s. ? 20 % o f 120 = w ? 
20
100
×120 = w ? w = 24 ii Let the cricketer score x runs in 4' s. ? 30 % o f 120 = x ? 
30
100
×120 = x ? x = 36 iii Let the 
( ) ( ) ( ) ( ) (
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
Page 3


      
  
  
  
  
  
      
       
         
     
      
Q u e s t i o n : 4
Find:
i
22% of 120
i i
25% of Rs 1000
i i i
25% of 10 kg
i v
16.5% of 5000 metre
v
135% of 80 cm
v i
2.5% of 10000 ml
S o l u t i o n :
( ) ( ) ( ) ( ) (
i 22 % of 120 =
22
100
×120 = 26. 4 ii 25 % of 1000 =
25
100
×1000 = 250 iii 25 % of 10 kg =
25
100
×10 kg =
25
10
kg =
5
2
kg = 2. 5 kg iv 16. 5 % of 5000 m =
16.5
100
×5000 m = 16. 5 ×50 m = 825 m
Q u e s t i o n : 5
Find the number a, if
i
8.4% of a is 42
i i
0.5% of a  is 3
i i i
1
2
%
of a is 50
i v
100% of a is 100
S o l u t i o n :
i 8. 4 % o f a is 42. i. e. , 
8.4
100
× a = 42 ? a =
42×100
8.4
? a = 500 ii 0. 5 % o f a is 3. i. e. , 
0.5
100
× a = 3 ? a =
3×100
0.5
? a = 600 iii 
1
2
% o f a is 50. i. e. , 
1
2
×
1
100
× a = 50 ? a = 50 ×200 ? a = 10000
Q u e s t i o n : 6
x is 5% of y, y is 24% of z. If x = 480, find the values of y and z.
S o l u t i o n :
Given: x =
5
100
y ? y =
100
5
x ? y = 20 xAlso, y =
24
100
z ? z =
100
24
yPutting x = 480 in the above equations, w e get: y = 20(480) = 9600 z =
100
24
×9600 = 40000
Q u e s t i o n : 7
A coolie deposits Rs 150 per month in his post office Savings Bank account. If this is 15% of his monthly income, find his monthly income.
S o l u t i o n :
Let his monthly income be Rs x . Then, 15 % o f x = 150 ?
15
100
x = 150 ? x =
150×100
15
= 1000 ? His monthly income is Rs 1000.
Q u e s t i o n : 8
Asha got 86.875% marks in the annual examination. If she got 695 marks, find the total number of marks of the examination.
S o l u t i o n :
Let x be the total number of marks of the examination. Then, 86. 875 % of x = 695 ?
86.875
100
x = 695 ? x =
695×100
86.875
= 800 ? The total number of marks of the examination is 800.
Q u e s t i o n : 9
Deepti went to school for 216 days in a full year. If her attendance is 90%, find the number of days on which the school was opened.
S o l u t i o n :
Let the school opened for x days in the given year. We have: 90 % o f x = 216 ?
90
100
x = 216 ? x =
216×100
90
= 240 ? The school opened for 240 days in the given year.
Q u e s t i o n : 1 0
A garden has 2000 trees. 12% of these are mango trees, 18% lemon and the rest are orange trees. Find the number of orange trees.
S o l u t i o n :
Let the number of orange trees be x. It is given that there are 2, 000 trees. While 12 % of them are mango trees, 18 % are lemon trees and the rest are orange trees. Now, (12 % o f 2000) +(
Q u e s t i o n : 1 1
Balanced diet should contain 12% of proteins, 25% of fats and 63% of carbohydrates. If a child needs 2600 calories in this food daily, find in calories the amount of each of these in his
daily food intake.
S o l u t i o n :
In a balanced diet of 2600 calories, 12 % is protein. ? Amount of protein in food intake = 12 % of 2600 =
12
100
×2600 = 312Similarly, a balanced diet contain s 25 % fats. ? Amount of fats
Q u e s t i o n : 1 2
A cricketer scored a total of 62 runs in 96 balls. He hit 3 sixes, 8 fours, 2 twos and 8 singles. What percentage of the total runs came in
i
Sixes
i i
fours
i i i
twos
i v
singles
S o l u t i o n :
i The cricketer hits 3 sixes. i. e. , 3 ×6 = 18 ? 
18
62
×100 = 29. 03 % ii The cricketer hits 8 fours. i. e. , 8 ×4 = 32 ? 
32
62
×100 = 51. 61 % iii The cricketer hits 2 twos. i. e. , 2 ×2 = 4 ? 
4
62
×100
Q u e s t i o n : 1 3
A cricketer hit 120 runs in 150 balls during a test match. 20% of the runs came in 6's, 30% in 4's, 25% in 2's and the rest in 1's. How many runs did he score in
i
6's
i i
4's
i i i
2's
i v
singles
What % of his shots were scoring ones?
S o l u t i o n :
i Let the cricketer score w runs in 6' s. ? 20 % o f 120 = w ? 
20
100
×120 = w ? w = 24 ii Let the cricketer score x runs in 4' s. ? 30 % o f 120 = x ? 
30
100
×120 = x ? x = 36 iii Let the 
( ) ( ) ( ) ( ) (
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
Q u e s t i o n : 1 4
Radha earns 22% of her investment. If she earns Rs 187, then how much did she invest?
S o l u t i o n :
Let the investment be Rs x. i. e. , 22 % of x = 187 ?
22
100
x = 187 ? x =
18700
22
= 850 ? Radha invest s Rs 850.
Q u e s t i o n : 1 5
Rohit deposits 12% of his income in a bank. He deposited Rs 1440 in the bank during 1997. What was his total income for the year 1997?
S o l u t i o n :
Let the total income for the year 1997 be Rs x. i. e. , 12 % o f x = 1440 ? 
12
100
x = 1440 ? x =
144000
12
? x = 12000 ? Rohit's total income was Rs 12, 000.
Q u e s t i o n : 1 6
Gunpowder contains 75% nitre and 10% sulphur. Find the amount of the gunpowder which carries 9 kg nitre. What amount of gunpowder would contain 2.3 kg sulphur?
S o l u t i o n :
Let the amount of gunpowder that contains 9 kg nitre be x kg. i. e. , 
75
100
× x = 9 ? 
100
75
=
x
9
? x =
900
75
? x = 12 ? The amount of gunpowder containing 9 kg nitre is 12 kg. Let the amount of gunpowder
Q u e s t i o n : 1 7
An alloy of tin and copper consists of 15 parts of tin and 105 parts of copper. Find the percentage of copper in the alloy?
S o l u t i o n :
Composition of the alloy = 15 parts of tin + 105 parts of copper = 120 parts ? Percentage of tin = 
15
120
×100 = 12. 5 %Also, percentage of copper = 
105
120
×100 = 87. 5 %
Q u e s t i o n : 1 8
An alloy contains 32% copper, 40% nickel and rest zinc. Find the mass of the zinc in 1 kg of the alloy.
S o l u t i o n :
Percentage of copper in the alloy = 32Percentage of nickel in the alloy = 40Percentage of zinc in the alloy = 100 -32 -40 = 28 ? Amount of zinc in 1 kg of the alloy = (0. 28 ×1) kg = 280 gm
Q u e s t i o n : 1 9
A motorist travelled 122 kilometres before his first stop. If he had 10% of his journey to complete at this point, how long was the total ride?
S o l u t i o n :
Let the length of total ride be x km. Then, 10 % of x = 122 ? 
10
100
x = 122 ? x = 1220 ? The length of total ride is 1, 220 km.
Q u e s t i o n : 2 0
A certain school has 300 students, 142 of whom are boys. It has 30 teachers, 12 of whom are men. What percent of the total number of students and teachers in the school is female?
S o l u t i o n :
Total number of female student s = 300 -142 = 158Total number of female teachers = 30 -12 = 18Total number of females = 158 +18 = 176Total population of the school = 300 +30 = 330
Q u e s t i o n : 2 1
Aman's income is 20% less than that of Anil. How much percent is Anil's income more than Aman's income?
S o l u t i o n :
Let Anil's income be x. Then, Aman's income = x -
20 x
100
=
8 x
10
Difference in the incomes of Anil and Aman = x -
8 x
10
=
2 x
10
? Percentage of the difference in the incomes of Anil and Aman to that
Q u e s t i o n : 2 2
The value of a machine depreciates every year by 5%. If the present value of the machine be Rs 100000, what will be its value after 2 years?
S o l u t i o n :
It is given that the value of the machine depreciates by 5 % every year. Present value of the machine = Rs 100000 ? For the first year, 5 % of 100000 = 
5
100
×100000 = Rs 5000 ? Value
Q u e s t i o n : 2 3
The population of a town increases by 10% annually. If the present population is 60000, what will be its  population after 2 years?
S o l u t i o n :
Present population = 60000It increases by 10 % ?annually. ? Increase in the population in the first year = 10 % of 60000 =
10
100
×60000 = 6000 ? Population after 1 year = 60000 +6000
Q u e s t i o n : 2 4
The population of a town increases by 10% annually. If the present population is 22000, find its population a year ago.
S o l u t i o n :
Let the population of the town one year ago = xNow, it is given that population of the town increases by 10 % annually. Present population = x + 10 % of x = x + 
10
100
× x = x + 
x
10
=
11 x
10
But
Q u e s t i o n : 2 5
Ankit was given an increment of 10% on his salary. His new salary is Rs 3575. What was his salary before increment?
S o l u t i o n :
Let the initial salary be Rs x. We know that: Salary before increment + increment given on salary = new salary ? x + 10 % o f x = 3575 ? x +
10
100
x = 3575 ? 100 x +10 x = 357500 ? 110
Q u e s t i o n : 2 6
In the new budget, the price of petrol rose by 10%. By how much percent must one reduce the consumption so that the expenditure does not increase?
S o l u t i o n :
We have to reduce the consumption such that the expenditure does not increase. For this, we use the following formula:
r
r+100
×100, where r = percentage rise in the price of the commodity
Q u e s t i o n : 2 7
Mohan's income is Rs 15500 per month. He saves 11% of his income. If his income increases by 10%, then he reduces his saving by 1%, how much does he save now?
( )
Page 4


      
  
  
  
  
  
      
       
         
     
      
Q u e s t i o n : 4
Find:
i
22% of 120
i i
25% of Rs 1000
i i i
25% of 10 kg
i v
16.5% of 5000 metre
v
135% of 80 cm
v i
2.5% of 10000 ml
S o l u t i o n :
( ) ( ) ( ) ( ) (
i 22 % of 120 =
22
100
×120 = 26. 4 ii 25 % of 1000 =
25
100
×1000 = 250 iii 25 % of 10 kg =
25
100
×10 kg =
25
10
kg =
5
2
kg = 2. 5 kg iv 16. 5 % of 5000 m =
16.5
100
×5000 m = 16. 5 ×50 m = 825 m
Q u e s t i o n : 5
Find the number a, if
i
8.4% of a is 42
i i
0.5% of a  is 3
i i i
1
2
%
of a is 50
i v
100% of a is 100
S o l u t i o n :
i 8. 4 % o f a is 42. i. e. , 
8.4
100
× a = 42 ? a =
42×100
8.4
? a = 500 ii 0. 5 % o f a is 3. i. e. , 
0.5
100
× a = 3 ? a =
3×100
0.5
? a = 600 iii 
1
2
% o f a is 50. i. e. , 
1
2
×
1
100
× a = 50 ? a = 50 ×200 ? a = 10000
Q u e s t i o n : 6
x is 5% of y, y is 24% of z. If x = 480, find the values of y and z.
S o l u t i o n :
Given: x =
5
100
y ? y =
100
5
x ? y = 20 xAlso, y =
24
100
z ? z =
100
24
yPutting x = 480 in the above equations, w e get: y = 20(480) = 9600 z =
100
24
×9600 = 40000
Q u e s t i o n : 7
A coolie deposits Rs 150 per month in his post office Savings Bank account. If this is 15% of his monthly income, find his monthly income.
S o l u t i o n :
Let his monthly income be Rs x . Then, 15 % o f x = 150 ?
15
100
x = 150 ? x =
150×100
15
= 1000 ? His monthly income is Rs 1000.
Q u e s t i o n : 8
Asha got 86.875% marks in the annual examination. If she got 695 marks, find the total number of marks of the examination.
S o l u t i o n :
Let x be the total number of marks of the examination. Then, 86. 875 % of x = 695 ?
86.875
100
x = 695 ? x =
695×100
86.875
= 800 ? The total number of marks of the examination is 800.
Q u e s t i o n : 9
Deepti went to school for 216 days in a full year. If her attendance is 90%, find the number of days on which the school was opened.
S o l u t i o n :
Let the school opened for x days in the given year. We have: 90 % o f x = 216 ?
90
100
x = 216 ? x =
216×100
90
= 240 ? The school opened for 240 days in the given year.
Q u e s t i o n : 1 0
A garden has 2000 trees. 12% of these are mango trees, 18% lemon and the rest are orange trees. Find the number of orange trees.
S o l u t i o n :
Let the number of orange trees be x. It is given that there are 2, 000 trees. While 12 % of them are mango trees, 18 % are lemon trees and the rest are orange trees. Now, (12 % o f 2000) +(
Q u e s t i o n : 1 1
Balanced diet should contain 12% of proteins, 25% of fats and 63% of carbohydrates. If a child needs 2600 calories in this food daily, find in calories the amount of each of these in his
daily food intake.
S o l u t i o n :
In a balanced diet of 2600 calories, 12 % is protein. ? Amount of protein in food intake = 12 % of 2600 =
12
100
×2600 = 312Similarly, a balanced diet contain s 25 % fats. ? Amount of fats
Q u e s t i o n : 1 2
A cricketer scored a total of 62 runs in 96 balls. He hit 3 sixes, 8 fours, 2 twos and 8 singles. What percentage of the total runs came in
i
Sixes
i i
fours
i i i
twos
i v
singles
S o l u t i o n :
i The cricketer hits 3 sixes. i. e. , 3 ×6 = 18 ? 
18
62
×100 = 29. 03 % ii The cricketer hits 8 fours. i. e. , 8 ×4 = 32 ? 
32
62
×100 = 51. 61 % iii The cricketer hits 2 twos. i. e. , 2 ×2 = 4 ? 
4
62
×100
Q u e s t i o n : 1 3
A cricketer hit 120 runs in 150 balls during a test match. 20% of the runs came in 6's, 30% in 4's, 25% in 2's and the rest in 1's. How many runs did he score in
i
6's
i i
4's
i i i
2's
i v
singles
What % of his shots were scoring ones?
S o l u t i o n :
i Let the cricketer score w runs in 6' s. ? 20 % o f 120 = w ? 
20
100
×120 = w ? w = 24 ii Let the cricketer score x runs in 4' s. ? 30 % o f 120 = x ? 
30
100
×120 = x ? x = 36 iii Let the 
( ) ( ) ( ) ( ) (
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
Q u e s t i o n : 1 4
Radha earns 22% of her investment. If she earns Rs 187, then how much did she invest?
S o l u t i o n :
Let the investment be Rs x. i. e. , 22 % of x = 187 ?
22
100
x = 187 ? x =
18700
22
= 850 ? Radha invest s Rs 850.
Q u e s t i o n : 1 5
Rohit deposits 12% of his income in a bank. He deposited Rs 1440 in the bank during 1997. What was his total income for the year 1997?
S o l u t i o n :
Let the total income for the year 1997 be Rs x. i. e. , 12 % o f x = 1440 ? 
12
100
x = 1440 ? x =
144000
12
? x = 12000 ? Rohit's total income was Rs 12, 000.
Q u e s t i o n : 1 6
Gunpowder contains 75% nitre and 10% sulphur. Find the amount of the gunpowder which carries 9 kg nitre. What amount of gunpowder would contain 2.3 kg sulphur?
S o l u t i o n :
Let the amount of gunpowder that contains 9 kg nitre be x kg. i. e. , 
75
100
× x = 9 ? 
100
75
=
x
9
? x =
900
75
? x = 12 ? The amount of gunpowder containing 9 kg nitre is 12 kg. Let the amount of gunpowder
Q u e s t i o n : 1 7
An alloy of tin and copper consists of 15 parts of tin and 105 parts of copper. Find the percentage of copper in the alloy?
S o l u t i o n :
Composition of the alloy = 15 parts of tin + 105 parts of copper = 120 parts ? Percentage of tin = 
15
120
×100 = 12. 5 %Also, percentage of copper = 
105
120
×100 = 87. 5 %
Q u e s t i o n : 1 8
An alloy contains 32% copper, 40% nickel and rest zinc. Find the mass of the zinc in 1 kg of the alloy.
S o l u t i o n :
Percentage of copper in the alloy = 32Percentage of nickel in the alloy = 40Percentage of zinc in the alloy = 100 -32 -40 = 28 ? Amount of zinc in 1 kg of the alloy = (0. 28 ×1) kg = 280 gm
Q u e s t i o n : 1 9
A motorist travelled 122 kilometres before his first stop. If he had 10% of his journey to complete at this point, how long was the total ride?
S o l u t i o n :
Let the length of total ride be x km. Then, 10 % of x = 122 ? 
10
100
x = 122 ? x = 1220 ? The length of total ride is 1, 220 km.
Q u e s t i o n : 2 0
A certain school has 300 students, 142 of whom are boys. It has 30 teachers, 12 of whom are men. What percent of the total number of students and teachers in the school is female?
S o l u t i o n :
Total number of female student s = 300 -142 = 158Total number of female teachers = 30 -12 = 18Total number of females = 158 +18 = 176Total population of the school = 300 +30 = 330
Q u e s t i o n : 2 1
Aman's income is 20% less than that of Anil. How much percent is Anil's income more than Aman's income?
S o l u t i o n :
Let Anil's income be x. Then, Aman's income = x -
20 x
100
=
8 x
10
Difference in the incomes of Anil and Aman = x -
8 x
10
=
2 x
10
? Percentage of the difference in the incomes of Anil and Aman to that
Q u e s t i o n : 2 2
The value of a machine depreciates every year by 5%. If the present value of the machine be Rs 100000, what will be its value after 2 years?
S o l u t i o n :
It is given that the value of the machine depreciates by 5 % every year. Present value of the machine = Rs 100000 ? For the first year, 5 % of 100000 = 
5
100
×100000 = Rs 5000 ? Value
Q u e s t i o n : 2 3
The population of a town increases by 10% annually. If the present population is 60000, what will be its  population after 2 years?
S o l u t i o n :
Present population = 60000It increases by 10 % ?annually. ? Increase in the population in the first year = 10 % of 60000 =
10
100
×60000 = 6000 ? Population after 1 year = 60000 +6000
Q u e s t i o n : 2 4
The population of a town increases by 10% annually. If the present population is 22000, find its population a year ago.
S o l u t i o n :
Let the population of the town one year ago = xNow, it is given that population of the town increases by 10 % annually. Present population = x + 10 % of x = x + 
10
100
× x = x + 
x
10
=
11 x
10
But
Q u e s t i o n : 2 5
Ankit was given an increment of 10% on his salary. His new salary is Rs 3575. What was his salary before increment?
S o l u t i o n :
Let the initial salary be Rs x. We know that: Salary before increment + increment given on salary = new salary ? x + 10 % o f x = 3575 ? x +
10
100
x = 3575 ? 100 x +10 x = 357500 ? 110
Q u e s t i o n : 2 6
In the new budget, the price of petrol rose by 10%. By how much percent must one reduce the consumption so that the expenditure does not increase?
S o l u t i o n :
We have to reduce the consumption such that the expenditure does not increase. For this, we use the following formula:
r
r+100
×100, where r = percentage rise in the price of the commodity
Q u e s t i o n : 2 7
Mohan's income is Rs 15500 per month. He saves 11% of his income. If his income increases by 10%, then he reduces his saving by 1%, how much does he save now?
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S o l u t i o n :
Mohan's saving = 11 % of 15500 =
11
100
×15500 = Rs. 1705
It is given that Mohan's income increases by 10 %. ? Increase in income =
10
100
×15500 = Rs 1550Increased income = Rs 15500 +1550 = Rs 17050Now, percentage of saving = 11
Q u e s t i o n : 2 8
Shikha's income is 60% more than that of Shalu. What percent is Shalu's income less than Shikha's?
S o l u t i o n :
Let Shalu's income be Rs x. ? Shikha's income = Rs x +
60 x
100
= Rs 
160 x
100
= Rs 
16 x
10
Difference in the incomes of Shikha and Shalu =
16 x
10
- x =
16 x-10 x
10
= Rs 
6 x
10
Percentage of the difference in the
Q u e s t i o n : 2 9
Rs 3500 is to be shared among three people so that the first person gets 50% of the second, who in turn gets 50% of the third. How much will each of them get?
S o l u t i o n :
Let x, y a n d z be the amounts received by the first, second and the third person, respectively. We have: x = 50 % of y =
50
100
y =
1
2
y ? y = 2 xAgain, y = 50 % of z =
1
2
z ? z = 2 y = 2(2 x) = 4 x
Q u e s t i o n : 3 0
After a 20% hike, the cost of Chinese Vase is Rs 2000. What was the original price of the object?
S o l u t i o n :
Let the original price of the object be x. According to the question, we have: 20 %of x + x = 2000 ?
20 x
100
+ x = 2000 ?
120
100
x = 2000 ? x =
200000
120
? x = 1666. 67Thus, the original price of the
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