Selina Solutions Concise Maths Class 7 Chapter 12 Simple Linear Equations (Including Word Problems) Exercise 12C is created by highly experienced faculty having vast experience in the education industry. The steps to be followed in solving equations that involve fractions are the main concept discussed under this exercise. Various solved examples are present before the exercise problems to help students analyze the questions that would appear in the annual exam. Students can access Selina Solutions Concise Maths Class 7 Chapter 12 Simple Linear Equations (Including Word Problems) Exercise 12C PDF, from the links which are available below.
Selina Solutions Concise Maths Class 7 Chapter 12: Simple Linear Equations (Including Word Problems) Exercise 12C Download PDF
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Access Selina Solutions Concise Maths Class 7 Chapter 12: Simple Linear Equations (Including Word Problems) Exercise 12C
Exercise 12C page: 141
Solve:
1. x/2 + x = 9
Solution:
It is given that
x/2 + x/1 = 9
Taking LCM
(x + 2x)/ 2 = 9
By cross multiplication
x + 2x = 9 × 2
3x = 18
So we get
x = 18/3 = 6
2. x/5 + 2x = 33
Solution:
It is given that
x/5 + 2x/1 = 33
Taking LCM
(x + 10x)/5 = 33
11x/5 = 33
By cross multiplication
11x = 5 × 33 = 165
So we get
x = 165/11 = 15
3. 3x/4 + 4x = 38
Solution:
It is given that
3x/4 + 4x/1 = 38
Taking LCM
(3x + 16x)/ 4 = 38
19x/4 = 38
By cross multiplication
19x = 38 × 4 = 152
So we get
x = 152/19 = 8
4. x/2 + x/5 = 14
Solution:
It is given that
x/2 + x/5 = 14
Taking LCM
(5x + 2x)/ 10 = 14
7x/10 = 14
By cross multiplication
7x = 14 × 10 = 140
So we get
x = 140/7 = 20
5. x/3 – x/4 = 2
Solution:
It is given that
x/3 – x/4 = 2
Taking LCM
(4x – 3x)/ 12 = 2
x/12 = 2
By cross multiplication
x = 12 × 2 = 24
6. y + y/2 = 7/4 – y/4
Solution:
It is given that
y/1 + y/2 = 7/4 – y/4
y/1 + y/2 + y/4 = 7/4
Taking LCM
(4y + 2y + y)/4 = 7/4
7y/4 = 7/4
7y = 7
So we get
y = 7/7 = 1
7. 4x/3 – 7x/3 = 1
Solution:
It is given that
4x/3 – 7x/3 = 1
By further calculation
-3x/3 = 1
So we get
-x = 1
x = – 1
8. m/2 + 3m/4 – m = 2.5
Solution:
It is given that
m/2 + 3m/4 – m/1 = 2.5
Taking LCM
(2m + 3m – 4m)/ 4 = 2.5
m/4 = 2.5
By cross multiplication
m = 2.5 × 4 = 10
9. 2x/3 + x/2 – 3x/4 = 1
Solution:
It is given that
2x/3 + x/2 – 3x/4 = 1
Taking LCM
(8x + 6x – 9x)/ 12 = 1
5x/12 = 1
By cross multiplication
5x = 1 × 12 = 12
So we get
x = 12/5 = 2 2/5
10. 3a/4 + a/6 = 66
Solution:
It is given that
3a/4 + a/6 = 66
Taking LCM
(9a + 2a)/ 12 = 66
11a/12 = 66
By cross multiplication
11a = 66 × 12 = 792
So we get
a = 792/11 = 72
11. 2p/3 – p/5 = 35
Solution:
It is given that
2p/3 – p/5 = 35
Taking LCM
(10p – 3p)/ 15 = 35
7p/ 15 = 35
By cross multiplication
7p = 35 × 15 = 525
So we get
p = 525/7 = 75
12. 0.6a + 0.2a = 0.4a + 8
Solution:
It is given that
0.6a + 0.2a = 0.4a + 8
Multiplying and dividing both numerator and denominator by 10
6/10a + 2/10a = 4a/10 + 80/10
Taking LCM
(6a + 2a)/ 10 = (4a + 80)/ 10
6a + 2a = 4a + 80
So we get
4a = 80
a = 80/4 = 20
13. p + 1.4p = 48
Solution:
It is given that
p + 1.4p = 48
Multiplying and dividing both numerator and denominator by 10
p + 14/10p = 48
Taking LCM
(10p + 14p)/ 10 = 48
24p/10 = 48
By cross multiplication
24p = 48 × 10 = 480
So we get
p = 480/24 = 20
14. 10% of x = 20
Solution:
It is given that
10% of x = 20
We can write it as
10/100 × x = 20
x/10 = 20
By cross multiplication
x = 20 × 10 = 200
15. y + 20% of y = 18
Solution:
It is given that
y + 20% of y = 18
We can write it as
y + 20/100 × y = 18
Taking LCM
(100y + 20y)/ 100 = 18
By cross multiplication
120y = 18 × 100 = 1800
So we get
y = 1800/120 = 15
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