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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 :
