**Telanagana SCERT Solution Class VII (7) Math Chapter 1 Integers.**

**Exercise 1 Solution**

(2)

(i) 17 – (-14)

= 17 + 14

= 31

(ii) 13 – (-8)

= 13 + 8

= 21

(iii) 19 – (-5)

= 19 + 5

= 24

(iv) 15 – 28/

= -13

(v)

25- 33

= – 8

(vi) 80 – (-50)

= 80 + 50

= 130

(vii) 150 – 75

= 75

(viii) 32 – (-18)

= 32 + 18

= 50

**Exercise 3**

(1)

(i) (-100) x (-6) =** 600**

(ii) (-3) x** (-1)** = 3

(iii) 100 x (-6) = **-600**

(iv) (-20) x (-10) =** 200**

(v) 15 x (-3) = **-45**

**(2)**

(i) 3 x (-1)

= -3

(ii) (-1) x 225

= -225

(iii) (-21) x (-30)

= 630

(iv) (-316) x (-1)

= 316

(v) (-15) x 0 x (-18)

= 0

(vi) (-12) x (-11) x (10)

= -12 x (-110)

= 1320

(vii) 9 x (-2) x (-6)

= 9 x 18

(viii) (-18) x (-5) x (-4)

= – 18 x 20

= – 360

(ix) (-1) x (-2) x (-3) x 4

= (-1) x (-2) x (-12)

= (-1) x (24)

= – 24

(x) (-3) x (-6) x (-2) x (-1)

= (-3) x (-6) x 3

= (-3) x (-18)

= 54

**(3)** Required forcing process temperature at 40^{0}c.

**∴** The rote at every hour = 5^{0}c

**∴** The rote at 10 hour = (5×10)^{0}c = 50^{0}c

Therefore, after 10 hours after the process begins = 40^{0} – 50^{0 }

= 10^{0}c

**(4)**

(i) Gopi gets 5 correct = 5 x 3

= 15 marks

And Gopi gets 5 incorrect = 5 x (-1)

= -5 marks

**∴ **Gopi scared = (15 + (-5)

= 15 – 5

= 10

(ii) Reshma gets 7 correct = 7 x 3

=21 marks

3 incorrect = 3 x (-1)

= -3 marks

**∴ **Reshma’s score = 21 + (-3)

= 21 – 3

=18

(iii) Reshmi get 3 correct = 3 x 3

= 9 marks

4 incorrect = 4 x (-1) marks

**∴ ** Reshmi scored = 9 + (-4)

= 9 – 4

= 5

**(5)**

(i) 3000 bags of basmati rice = 3000 x 10 Rs.

5000 bags of non- basmati rice = 5000 x 5 Rs.

**∴ **Net profit = (30000 – 25000)

= 5000

(ii) Let x be the number of bags of basmati rice.

**∴ **10x = 6400 x 5

X = 6400 x 5/10

X = 3200

**(6)**

(i) (-3) x **(-9)** = 27

(ii) 5 x **(-7)** = -35

(iii) **7** x (-8) = -56

(iv) **(-11) **x (-12) = 132

**Exercise 5**

**(1) **

(i) L.H.S. = 18 x [7 + (-3)]

= 18 x (+4)

= 72

R.H.S. = [18 x 7] + [18 x (-3)]

= 126 + (-54)

= 72

**∴ **L.H.S. = R.H.S. (Proved)

(ii) L.H.S. = (-21) x [(-4) + (-6)]

= -21 x (-10)

= 210

R.H.S. = [(-21) x (-4)] + [(-21) x (-6)]

= 24 + 126

= 210

**∴ **L.H.S. = R.H.S. (Proved)

**(2)**

(i) (-1) x a = -a

(ii) (-1) x (-5)

= 5

(3)

(i) 26 x (-48) + (-48) x (-36)

= (-48) x [26 + (-36)]

= -48 x – 10

= 480

(ii) 8 x 53 x (-125)

= 424 x – 125

= -53000

(iii) 15 x (-25) x (-4) x (-10)

= 15 x (-25) x 40

= 15 x (-1000)

= -15,000

(iv) (-41) x 102

= -4182

(v) 625 x (-35) + (-625) x 65)

= -625 x (35 + 65)

= -625 x 100

= -62500

(vi) 7 x (50-2)

= (7 x 50) – (7 x 2)

= 350 – 14

= 336

(vii) (-17) x (-29)

= 493

(viii) (-57) x (-19) + 57

= -57 x [-19 + (-1)]

= -57 x (-220)

= 1140

**Exercise – 6**

(1)

(i) (-25) ÷** (-1) **= 25

(ii) **(-49)** ÷ 1 = -49

(iii) 50 ÷ 0 = **not difined**

(iv) 0 ÷ 1 = **0**

**Exercise – 7**

**(1)**

(i) Bharati get correct answer = 9

Incorrect answer = 15 – 9

= 6

**∴**Her scored = (9 x 4) + [6 x (-2)]

= 36 + (-12)

= 36 – 12

= 24

(ii) Hema attempts 5 questions she scored = 5 x 4

=20

**(2)**

(i) The company profit on 7000 bags of white connect = 9 x 7000 Rs

= 63,000 Rs.

The company loss on 6000 bags of grey cement = 5 x 6000

= 30,000

**∴ **Net profit = (63000-30000)

= 33,000

(ii) Let, the number of white cement bags be = X

**∴ **9x = 5400 x 5

X = 5400 / 9 x 5

X = 600 x 5

= 3000

**(3)** Temperature at 12 noon = 10^{0}c above zero

= 10^{0}c

Decrease at 2^{0}c/hour.

Final temperature = 8^{0}c below zero

= -8^{0}c

Change in temperature = 10 – (-8)

= 10 + 8

= 18^{0}c

Rate of decrease = 18/hour

Time = 18/2

= 9 hours

So, the temperature is 8^{0}c below zero at 9 p.m.

The temperature at midnight = 12 am

Time = 10 – 2 x (12)

= 10 – 24

= -14

Thus, the temperature at midnight is 14^{0}c below zero.

**(4)**

(i) Radhika scored = 20marks

She get correct answers = 12 x 3

= 36

Let, Radhika attempt incorrect answer be x

**∴ **-2x = 20 – 36

X = -16/-2

= 8

Thus, the number of incorrect answer is 8

(ii) Mohini scored = -5 marks

She get correct answer = 7 x 3

= 21 marks

Let, Mohini attempt incorrect answer be X

**∴ **-2x = -5 -21

x = -26/-2

= 13

Thus, the number of incorrect answer is 13

**(5)** The elevator has to travel 10m till the ground, then 350m more.

So, the total distance to travel is (350 + 10) m

= 360m

Rate of elevator’s speed = 6m/minute

**∴ **Time = distance/speed

= 360/6

= 60 minutes

= 1 hour