# Mathsight Class 7 Solutions Chapter 7

## 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 :

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

∴ 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 :

👉 Chapter 6

Updated: May 27, 2023 — 6:32 am