Class 8 Maths Chapter 2 Exercise 2.2 NCERT Solution – Linear Equations in one Variable

NCERT Class 8 Math Exercise 2.2 Solution of Chapter 2 Linear Equations in one Variable with explanation. Here we provide Class 8 Maths all Chapters in Hindi for cbse, HBSE, Mp Board, UP Board and some other boards.

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NCERT Class 8 Maths Chapter 2 Linear Equations in one Variable Exercise 2.2 Solution in english Medium.

Class 8 Maths Chapter 2 Exercise 2.2 Solution

1. If you subtract ½ from a number and multiply the result by ½, you get ⅛ . What is the number?
Solution:
Let the number be x.
According to question,
( x – ½ ) × ½ = ⅛
x/2 – ¼ = ⅛
x/2 = ⅛ + ¼
x/2 = ⅜
x = ⅜×2
x = ¾

2. The perimeter of a rectangular swimming pool is 154 m. Its length is 2 m more than twice its breadth. What are the length and the breadth of the pool?
Solution:
Perimeter of a rectangular swimming pool = 154 m.
Let the breadth of rectangle = x
According to question,
Length of rectangle = 2x + 2
Perimeter of rectangle
= 2( 2x +2 + x)
= 154
2( 2x +2 + x) = 154
2(3x + 2) = 154
6x + 4 = 154
6x = 154 -4
6x = 150
x = 150/6
x = 25
Length = 2×25 + 2 = 52m.

3. The base of an isosceles triangle is 4/3 cm. The perimeter of the triangle is 4_2/15cm.
What is the length of either of the remaining equal sides?
Solution:
Base of isosceles triangle = 4/3
Perimeter of triangle = 4_2/15 cm = 62/15cm
Let the length of equal sides of triangle be x.
According to the question,
4/3 + x + x = 62/15
2x = 62/15 – 4/3
2x = (62- 20 )/15
2x = 42/15
x = 62/15 × ½
x = 42/30 cm
x = 7/5 cm
The length of either of the remaining equal sides aer 7/5 cm.

4. Sum of two numbers is 95. If one exceeds the other by 15, find the numbers.
Solution:
Let one of the numbers be = x.
Then, the other number becomes x + 15. According to the question,
x + x + 15 = 95
2x = 95 – 15
2x = 80
x = 80/2
x = 40
First number = x = 40
And, other number = x + 15 = 40 + 15 = 55.

5. Two numbers are in the ratio 5:3. If they differ by 18 , what are the numbers?
Solution:
Let the two numbers be 5x and 3x.
According to the question,
5x – 3x = 18
2x = 18
x = 18/2
x = 9
The numbers are 5x = 5 × 9 = 45
And 3x = 3 × 9 = 27.

6. Three consecutive integers add up to 51. What are these integers?
Solution:
Let the three consecutive integers be x, x + 1, x +2.
According to the question,
x + x + 1 + x + 2 = 51
3x + 3 = 51
3x = 51 – 3
3x = 48
x = 48 /3
x = 16
thus, the integers are
x = 16
x + 1 = 17
x + 2 = 18

7. The sum of three consecutive multiples of 8 is 888. Find the multiples.
Solution:
Let the three consecutive multiples of 8 be 8x, 8( x + 1 ), 8( x + 2 ).
According to the question,
8x + 8(x + 1 ) + 8( x + 2 ) = 888
8( x + x + 1 + x + 2 ) = 888 ( taking 8 as common )
8( 3x + 3 ) = 888
3x + 3 = 888/8
3x + 3 = 111
3x = 111 – 3 = 108
x = 108/3
x = 36
Thus, the three consecutive multiples of 8 are:
8x = 8 × 36 = 288
8( x + 1 ) = 8 × 37 = 296
8( x + 2 ) = 8 × 38 = 304

8. Three consecutive integers are such that when they are taken in increasing order and multiplied by 2,3 and 4 respectively, they add up to 74. Find these.
Solution:
Let the three consecutive integers are x, x + 1, x +2.
According to the question,
2x + 3( x + 1 ) + 4( x + 2 ) = 74
2x + 3x + 3 + 4x + 8 = 74
9x + 11 = 74
9x = 74 – 11
9x = 63
x = 63/9
x = 7
Thus, the numbers are:
x = 7
x + 1 = 8
x + 2 = 9

9. The ages of Rahul and Haroon are in the ratio 5:7. Four years later the sum of their ages will be 56 years. What are their present ages?
Solution:
Let the ages of Rahul and Haroon be 5x and 7x.
According to the question,
5x + 4 + 7x + 4 = 56
12x + 8 = 56
12x = 56 – 8
12x = 48
x = 48/12
x = 4
Therefore,
Present age of Rahul = 5x = 5 × 4 = 20
And, Present age of Haroon = 7x = 7 × 4 = 28

10. The number of boys and girls in a class are the ratio 7:5. The number of boys is 8 more than the number of girls. What is the total class strength?
Solution:
Let the number of boys be 7x and girls be 5x.
According to the question,
7x = 5x +8
7x – 5x = 8
2x = 8
x = 8/4
x = 2
Therefore, Number of boys = 7 × 4 = 28
And, Number of girls = 5 × 4 = 20
Total number of students = 20 + 28 = 48

11. Baichung’s father is 26 years younger than Baichung’s grandfather and 29 years older than Baichung. The sum of the ages of all the three is 135 years. What is the age of each one of them?
Solution:
Let the age of Baichung’s father be x.
Then, the age of Baichung’s grandfather = x + 26.
and, Age of Baichung = x – 29.
According to the question,
x + x + 26 + x – 29 = 135
3x – 3 = 135
3x = 135 + 3
3x = 138/3
x = 46
Age of Baichung’s father = x = 46
Age of Baichung’s grandfather = x +26 = 72
Age of Baichung = x – 29 = 17

12. Fifteen years from now Ravi’s age will be four times his present age. What is Ravi’s present age?
Solution:
Let the present age of Ravi be x.
Fifteen years later, Ravi age will be x + 15years.
According to the question,
x + 15 = 4x
4x – x = 15
3x = 15
x = 15/3
x = 5
Therefore, present age of Ravi = 5 years.

13. A rational number is such that when you multiply it by 5/2 and add 2/3 to the product, you get, -7/12. What is the number?
Solution:
Let the rational number be x.
According to the question,
x × (5/2) + 2/3 = -7/12
5x/2 + 2/3 = -7/12
5x/2 = -7/12 -2/3
5x/2 = ( -7 -8)/12
5x/2 = -15/12
5x/2 = -5/4
x = (-5/4) × (2/5)
x = -10/20
x = -1/2
Therefore, the rational number is -1/2.

14. Lakshmi is a cashier in a bank. She has currency notes of denominations 100, 50 and 10, respectively. The ratio of the number of these notes is 2:3:5. The total cash with Lakshmi is 4,00,000. How many notes of each denomination does she have?
Solution:
Let the numbers to notes of Rs.100, Rs.50, Rs.10, be 2x, 3x, and 5x respectively.
Value of Rs.100 = 2x × 100 = 200x
Value of Rs.50 = 3x × 50 = 150x
Value of Rs.10 = 5x × 10 = 50x.
According to the question,
200x + 150x + 50x = 4,00,000
400x = 4,00,000
x = 4,00,000/400
x = 1000
Numbers of Rs.100 notes = 2x = 2000
Numbers of Rs.50 notes = 3x = 3000
Numbers of Rs.10 notes = 5x = 5000

15. I have a total of Rs.300 in coins of denomination Rs.1, Rs.2 and Rs.5. The number of Rs.2 coins is 3 times the number of Rs.5 coins. The total number of coins is 160. How many coins of each denomination are with me?
Solution:
Let the number of Rs.5 coins be x.
Then,
Number of Rs.2 coins = 3x
Number of Rs.1 coins = 160 – 4x
Now,
Value of Rs.5 coins = x × 5 = 5x
Value of Rs.2 coins = 3x × 2 = 6x
Value of Rs.1 coins = (160 – 4x) × 1 = 160 -4x
According to the question,
5x +6x + 160 – 4x = 300
11x + 160 – 4x = 300
7x = 300 – 160
7x = 140
x = 140/7
x = 20
Number of Rs.5 coins = x = 20
Number of Rs.2 coins = 3x = 60
Number of Rs.1 coins = 160 – 4x = 160 -80
= 80

16. The organisers of an essay competition decide that a winner in the competition gets a prize of Rs.100 and a participant who does not win gets a prize of Rs.25. The total prize money distributed is Rs.3000. Find the number of winners, if the total number of participants is 63.
Solution:
Let the numbers of winner be x.
Then, the number of participants who didn’t win = 63 – x
Total money given to the winner = x × 100 = 100x
Total money given to participant who didn’t win = 25( 63 – x )
According to the question:
100x + 25( 63 – x ) = 3,000
100x + 1575 – 25x = 3,000
75x = 3,000 – 1575
75x = 1425
x = 1425/75
x = 19
Therefore, the number of winners are 19.

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