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**Mathsight Class 7 Solutions Chapter 7 Simple Linear Equations**

Welcome to NCTB Solutions. Here with this post we are going to help 7th class students to solve MathSight Class 7 Mathematics Book, Chapter 7, Simple Linear Equations. Here students can easily get all the exercise questions solution for Chapter 7, Simple Linear Equations Exercise 7.1, 7.2, 7.3, and 7.4

**Simple Linear Equations Exercise 7.1 Solution : **

**Question no – (1)**

**Solution : **

Correct option – (a)

= 5x + 5

= 35

**Question no – (2)**

**Solution :**

**(a)** 5x + x/2

= 9

**(b)** (3x + 5)

= 17

**(c)** x/2

= 15

**(d)** 32x + 5/2

= 27

**(e)** 2 + x

= 8

**(f)** x + 10

= 38

**Question no – (3)**

**Solution :**

Profit of this week,

= 1000-750

= 250 Rs

**Question no (4)**

**Solution :**

**(a)** Leela have,

= x + 10

= 18

Or, x = 18 – 10

= 8

**(b)** 18x = 108

Or, x = 108/18

= 6

**(c)** c + 3 = 12

Or, c = 12 – 3

= c = 9

**Question no – (5)**

**Solution :**

7x = 217

Or, x = 217/7

= 31

**Simple Linear Equations Exercise 7.2 Solution : **

**Question no – (1)**

**Solution :**

Correct option – (c)

= 3x – 4

= -13,

x = -2

**Question no – (2)**

**Solution :**

**(a)** x + 4 = 7 → 1 + 4 ≠ 7

2 + 4 ≠ 6

3 + 4 = 7

∴ x = 3

**(b)** 2x = 18 → 2.7 ≠ 14

2.8 ≠ 16

2.9 = 19

∴ x = 9

**(c)** 9 – x = 3 → 9 – 4 ≠ 5

9 – 5 ≠ 4

9 – 6 = 3

∴ x = 6

**(d)** x/4 = 12 → 40/4 ≠ 12

41/4 ≠ 12

42/4 ≠ 12

43/4 ≠ 12

45/4 ≠ 12

46/4 ≠ 12

47/4 ≠ 12

48/4 ≠ 12

∴ x = 48

**Question no – (3)**

**Solution :**

**(a)** L.H.S, 13 + X = 145

Or, 13 + 32 = 145 [p]

**(b)** L.H.S, 13y = -91

Or, 13(-7) = -91

**(c)** L.H.S, 45/x = -15

Or, 45/-3 = -15

**(d)** L.H.S, d – 8 = 19

Or, -17 – 8 ≠ 19

**(e)** L.H.S, 5 + x = -7

Or, 5 – 12 = -7

**(f)** L.H.S, m – 5 = 0

Or, 0 – 5 – 5 ≠ 0

**Question no – (4)**

**Solution : **

= 62 – 48

= 14 coins

**Question no – (6)**

**Solution :**

**(a)** x × 3

= 18

**(b)** x × 36/12

= 18

**Question no – (7)**

**Solution :**

32 – (-3)

= 32 + 3

= 35°c

**Question no – (8)**

**Solution :**

= 72/4

= 18

**Simple Linear Equations Exercise 7.3 Solution : **

**Question no – (1)**

**Solution :**

Correct option – (c)

x – 17 = -2

**Question no – (2)**

**Solution :**

**(a)** -x + 14 = 21

Or, -x +14 – 14

= 21 – 14

**(b)** 2x + 12 = 64

Or, 2x + 12 – 12 = 64 – 12

Or, 2x = 52

Or, x = 52/2 = 26

**(c)** 4x – 6 = 3

Or, 4x – 6 + 6 = 3 + 6 = 9

Or, 4x = 9

Or, x = 9/4

**(d)** 2 (m + 6) = 3 (m – 10

Or, 2 m + 12 = 3 m – 30

Or, 2 m + 12 -12

= 3 m – 30 – 12

Or, 2 m = 3 m – 42

Or, 3 m – 2 m = 42

Or, m = 42

**Question no – (3)**

**Solution :**

**(a)** x + 7 = 14

Or, 7 + 7 = 14

**(b)** 2x + 5 = 20

Or, 2.5 + 5 = 20

Or, 10 + 5 ≠ 20

**(c)** x/3 = 3

Or, 9/3 = 3

**(d)** – 3 (-4) + 4 = 16

Or, – 12 + 4 ≠ 16

**Question no – (4)**

**Solution :**

**(a)** 7x – 3x + 8 = x + 2

Or, 4x – x = 2 – 8

Or, 3x = – 6

Or, x = – 6/3 = -2

**(b)** x + (x + 6) = (x + 8) + 21

Or, x + x + 6 = x + 29

Or, x = 29 – 6 = 23

**(c)** 2 (x + 10) = 3 (x – 20)

Or, 2x + 20 = 3x – 60

Or, 3x – 2x = 60 + 20

Or, x = 80

**(d)** x – 5 / 7 – 8 = 2x + 4 / 5

Or, x – 5 – 56 / 7 = 2x + 4 / 5

Or, 5x – 25 – 280 = 14x + 28

Or, 14x – 5x = – 280 – 25 – 28

Or, 9x = – 333

Or, x = -333 / 9

= – 37

**Question no – (5)**

**Solution :**

Let, lifespan of a cat = x

According Question,

x – 3 = 13

Or, x = 13 + 3

x = 16

**Question no – (7)**

**Solution :**

Let, after x year,

(31 + x) = 3 (5 + x)

Or, 3.1 + x = 15 + 3x

Or, 3x – x = 31 – 15 = 16

Or, 2x = 16

Or, x = 16/2

x = 8

**Question no – (8)**

**Solution :**

x – 249 = 350

Or, x = 350 + 249

= 599

**Question no – (9)**

**Solution :**

**(a)** 3x = 6

**(b)** x – 2 = 3

**(c)** x – 2

= 6 – 2 = 4

**(d)** 2 (x – 2)

= 4 × 2 = 8

**Question no – (10)**

**Solution :**

Let, number of 10 rupee’s coin = x.

Number of 5 rupee’s coin = y.

According to question,

Y = 4x …..(i)

According to question,

10x + 5y = 90

Or, 10x + 5 (4x) = 90

Or, 10x + 20x = 90

Or, 30x = 90

Or, x = 90/30

= x = 3

**Question no – (11)**

**Solution :**

x – 75 =150

Or, x = 150 + 75

x = 225

**Question no – (12)**

**Solution :**

12 + x = 20

Or, x = 20 + 12

x = 32

**Simple Linear Equations Exercise 7.4 Solution : **

**Question no – (1)**

**Solution :**

Correct option – (d)

The value of x = 0 will make the equation true.

**Question no – (2)**

**Solution :**

**(a)** 3y + 7 = 28

Or, 3y = 28 – 7

Or, 3y = 21

Or, y = 21/3 = 7

**(b)** 2y + 6 / 9 + 10 = 14

Or, 2y + 6 + 90 / 9 = 14

Or, 2y + 96 = 126

Or, 2y = 126 – 96 = 30

Or, y = 30/2 = 15

**(c)** 17x/3 + 3 = 54

Or, 17x + 9 / 3 = 54

Or, 17x + 9

= 54 × 3 = 162

Or, 17x = 162 – 9 = 153

Or, x = 153 / 17 = 9 .

**(d)** 2x + 5 / 3 = 3x – 10

Or, 2x + 5 = 9x – 30

Or, 9x – 2x = 30 + 5

Or, 7x = 35

Or, x = 35 / 7 = 5

**(e)** 2z/3 = 3z/8 + 7/12

Or, 2z/3 – 3z/8 = 7/12

Or, 16z – 9 z / 24 = 7/12

Or, 7z = 4 × 24 / 12

Or, z = 7 × 2/7 = 2

**(f)** 4z + 8 = 7z + 11

Or, 7z – 4z

= 8 – 11 = – 3

Or, 3z = – 3

Or, z = – 1

**(g)** 3a + 2 / 11 = a + 5 / 8

Or, 24a – 16 = 11a + 55

Or, 24a – 11a

= 55 – 16 = 39

Or, 13a = 39

Or, a = 39/13 = 3

**(h)** y/3 + y/8 = 1/12

Or, 8y + 3y / 24 = 1/12

Or, 11y = 2

Or, y = 2/11

**(i)** 8 (n-1) = 10 – 2n

Or, 8n – 8 = 10 – 2n

Or, 8n + 2n = 10 + 8 = 18

Or, 10n = 18

Or, n = 18/10 = 9/5

**Question no – (3)**

**Solution :**

Let, one part is = x

According question,

x + (x + 18) = 38

Or, 2x = 38 – 18 = 20

Or, x = 20/2 = 10

∴ One part = x = 10

∴ Other x = 10 + 18 = 28

**Question no – (4)**

**Solution :**

Let, Breadth = x

Length = 5 + x

According to question,

2[x + (5+x)] = 250

Or, 2x + 5 = 250/2 = 125

Or, 2x = 125 – 5 = 120

Or, x = 120/2 = 60

**Question no – (5)**

**Solution :**

ax + b = – 4

**Question no – (6)**

**Solution :**

**(a)** 8 – 2x = 3x – 7

Or, 3x + 2x

= 7 + 8 = 15

Or, 5x = 15

Or, x = 15/8 = 3

**(b)** 4 (x-1) = 6x – 8

Or, 4x – = 6x – 8

Or, 6x – 4x

= 8 – 4 = 4

Or, 2x = 4

Or, x = 4/2 = 2

**(c)** 4x – 1 = x + 11

Or, 4x – x = 11 + 1 = 12

Or, 3x = 12

Or, x = 12/3 = 4

**Question no – (7)**

**Solution :**

According to question,

x + 1 + 90 + 5 = 100

Or, x + 96 = 100

Or, x = 100 – 96 = 4

**Question no – (8)**

**Solution :**

Let, cost of bat = x

Cost of ball = x/5

According to question,

x + x/5 = 1200

Or, 2x + x / 5 = 1200

Or, 6x = 1200 × 5

Or, x = 1200 × 5/6 = 1000

∴ Bat = 1000 Rs

∴ Ball = 100/5 = 200 Rs

**Question no – (9)**

**Solution :**

Let, B = x

L = 2x

Now according to question,

[2(x = 2x)] × 15 = 900

Or, (3x)

= 400/2 × 15

Or, x = 900/2 × 15 × 3

= 10

∴ Breadth = 10

∴ Length = 10 × 2

= 20 m

Thus, the breadth will be 10 m and length will be 20 m.

**Question no – (10)**

**Solution :**

Let, one bag wt = x

Other bag wt = x + 5

According to question,

X + (x + 5) = 31

Or, 2x + 5 = 31

Or, 2x = 31 – 5 = 26

Or, x = 26/2 = 13 kg.

∴ one bag = 13 kg

∴ Other bag = 13 + 5 = 18 kg

**Previous Chapter Solution : **