# Mathsight Class 7 Solutions Chapter 8

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## Mathsight Class 7 Solutions Chapter 8 Commercial Mathematics

Welcome to NCTB Solutions. Here with this post we are going to help 7th class students to solve MathSight Class 7 Mathematics Book, Chapter 8, Commercial Mathematics. Here students can easily get all the exercise questions solution for Chapter 8, Commercial Mathematics Exercise 8.1, 8.2, 8.3 and 8.4

Commercial Mathematics Exercise 8.1 Solution :

Question no – (1)

Solution :

Day = 18 × 12 / 15

= 72/5

= 14 2/5 days

Question no – (2)

Solution :

Nambar of slices

= 15 × 30 / 16

= 225 / 8

28 1/8

Question no – (3)

Solution :

Wet of orange,

= 1000 × 7.5/50

= 150 kg .

Question no – (4)

Solution :

Time needed,

= 75 × 5 / 60

= 25 / 4

= 5 5/4 hr.

Question no – (5)

Solution :

Contribution,

= 200 × 7500 /500

= 30000 Rs.

*We should stand with our nation at any Problem of our country through economically and physically.

Question no – (6)

Solution :

Time = 4 × 8 /5

= 32/5

= 6  2/5 hr.

Question no – (7)

Solution :

= 15 × 600 / 10

= 900

Question no – (8)

Solution :

Day = 8 × 16/10

= 64/5

= 12 4/5 days

Question no – (9)

Solution :

Anil digs 10 days = 1 work

∴ Anil digs 1 days = 1/10 work .

Sunil digs 15 days = 1 work .

∴ They digs 1 days together

= 1/10 + 1/15

= 3 + 2/30

= 5/30

= 1/6 work .

∴ they digs 1 well = 6 days .

Question no – (10)

Solution :

Calories in ⇒ whole milk ,

100 × 438 / 300 ,

= 146 cal>

Calories in ⇒ low fat milk ,

100 × 408 / 400 ,

= 102 cal >

Calories ⇒ skim milk,

= 100 × 415 / 500 ,

= 83 cal .

(a) whole milk = 146 cal .

Calories ⇒ whole milk ,

100 × 828 / 300 ,

= 276 mg

Calories ⇒  low fat milk ,

100 × 1160 / 400 ,

= 290 mg

Calories ⇒ skim milk,

= 100 × 1530 / 500,

⇒ 306 mg

(b) whole milk = 276 mg

(c) low fat milk

Commercial Mathematics Exercise 8.2 Solution :

Question no – (1)

Solution :

(a) 2/5 = 2/5 × 100 = 40%

(b) 3/4 = 3/4 × 100 = 75%

(c) 7/8 = 7/8 × 100 = 175/2

= 87 1/2%

(d) 1/10 = 1/10 × 100 = 10%

(e) 2 1/4 = 9/4 × 100 = 225%

Question no – (2)

Solution :

(a) 43% = 43/100

(b) 22.5% = 22.5/100 = 225/100

= 9/40

(c) 72.5% = 72.5/100

= 725/1000

= 29/40

(d) 125% = 125/100 = 5/4

(e) 110% = 110/100 = 11/10

Question no – (3)

Solution :

(a) 42% = 42/100 = 0.42

(b) 6.5% = 65/1000 = 0.065

(c) 0.05% = 5/1000 = 0.0005

(d) 33 1/3% = 100/3 × 100 = 0.33

(e) 92% = 92/100 = 0.92

Question no – (4)

Solution :

(a) 0.225 = 225/100 × 100 = 225%

(b) 4.75 = 475/100 × 100 = 475%

(c) 0.004 = 4/100 × 100 = 4%

(d) 1.5 = 15/10 × 100 = 100%

(e) 4.6 = 46/10 × 100 = 460%

Question no – (5)

Solution :

(a) 52 : 78 = 52/78 × 100 = 200/3%

(b) 45 : 20 = 45/20 × 100 = 225%

(c) 7.5 : 22.5 = 7.5/22.5 × 100 = 33.33%

(d) 4 : 7 = 4/7 × 100 = 400/7%

(e) 7 : 8 = 7/8 × 100 = 175/2%

Question no – (6)

Solution :

(a) 4.75%

= 475/1000

= 19/40

= 19:40

(b) 90%

= 90/100

= 9:10

(c) 1.1%

= 11/1000

= 11:1000

(d) 0.15%

= 15/10000

= 3:2000

(e) 82.2%

= 825/1000

= 33/40

= 33:40

Question no – (7)

Solution :

(a) 12 1/2% of 60

= 25/2 × 100 × 60

= 75/10

= 7.5

(b) 37.5% of 150

= 375/100 × 100 × 150

= 225/4

= 56.25

(c) 52% of 165

= 52/100 × 165

= 85.8

(d) 33 1/3% of  200

= 100/3 ×100 × 200

= 66.66

(e) 0.8% of 40

= 8/10×100 × 40

= 0.32

Question no – (8)

Solution :

Red ball %

= 100 × 8/20

= 40%

Question no – (9)

Solution :

Number of English book,

= 4/(4 + 5 + 1) × 1500

= 4/10 × 1500

= 600

Number of Hindi book

= 5/(4+5+1) × 1500

= 5/10 × 1500

= 750

Nambar of urdu book

= 1/(4+5+1) × 1500

= 1/10 × 1000

= 150

Question no – (10)

Solution :

Let, total income = x

∴ saving = x – 14000

According to question,

30x/100 = x – 14000

Or, 30x

= 100x – 1400000

Or, 100x – 30x

= 1400000

Or, 70x

= 1400000

Or, x

= 1400000/70

Or, x

= 20000

∴ total income = 20,000 rs

Saving  = 20000 – 14000

= 6000 rs

Question no – (11)

Solution :

(a) let, whole quantities = x

According to question

X × 12.5/100 = 125

Or, x = 125×100×10 / 125

= 1000

(b) let, whole quantities = x

According to question

X × 40/100 = 800

Or, x = 800×100/40

= 2000

(c) let, whole quantities = x

According to question

5/100 × x = 12.5

Or, x = 125×100/10×8

Or, x = 250

(d) Let, whole quantities = x

According to question

45/100 × x = 9000

Or, x = 4000×100 / 45

Or, x = 20000

(e) Let, whole quantities = x

According to question

7.5/100 × x = 15

Or, x = 15×100×10/75

= 200

Question no – (12)

Solution :

Total toffees = 16

∴ jai get toffees

= 25/100 × 16

= 4

Viru get toffees,

= 75/100 × 16

= 12

Question no – (13)

Solution :

New price,

= 1050×[100+12.5]/100

= 1050×112.5/100

= 1,181.25 Rs

Question no – (14)

Solution :

Total sample= 0.24 gv

Boron contain,

= 0.096/0.24 × 100

= 40%

Oxygen contain

= 0.144/0.24 × 100

= 60%

Question no – (15)

Solution :

Y = 180x/100

= 9x/5

= 1.8x

Y is 1.8 time of x .

∴ y is greater then x

Commercial Mathematics Exercise 8.3 Solution :

Question no – (1)

Solution :

(a) Selling Price (S.P)

= 920 × 106/100

= 975.2 Rs

(b) Selling Price (S.P)

= 1080 × 92.5/100

= 999 Rs

Question no – (2)

Solution :

(a) C.P = 360×112.5/100

= 405 Rs

(b) C.P = 1539×90/100

= 1385.1 Rs

Question no – (3)

Solution :

C.P of 200 books

= 200×180

= 36000

S.P of 200 books,

= 36000 × 115/100

=  41,400 rs

Profit = 41400 – 36000

= 5,400 Rs

Question no – (4)

Solution :

Let, C.P of 1 pen = 1 Rs

C.P of 20 pen = 20 Rs

S.P of 20 pen = 22 Rs

Profit % = 22 – 20/20 × 100

= 2/20 × 100

= 10%

Question no – (5)

Solution :

Total expenditure,

= 225400 + 10000

= 235400 Rs

Loss, = 235400 – 225000

= 10400

Loos %

= 10400 × 100/235400

= 4.41 %

Question no – (6)

Solution :

1 dozen = 12 pieces

∴ C.P of 12 pieces = 35 Rs

∴ S.P of 12 pieces

= 35 × 120/100

= 42 rs

S.P of 1 pieces

= 42/12

= 3.5 rs

Question no – (7)

Solution :

Sp of two toaster,

= 900 ×  2

= 1800 rs

C.P of toaster,

= 100 × 900 /120

= 45006

= 750 Rs

C.P of towster

= 100×900/80

= 4500/4

= 1125 Rs

Total C.P = 1125 + 750

= 1875 Rs

gain = 1875 – 1800

= 75 Rs

gain % = 75/1875 × 100

= 4 %

Question no – (8)

Solution :

C.P of 15 chair

= 15 × 450

= 6750 Rs

S.P of 12 chair

= 12 × 512

= 6144 Rs

S.P of 3 chair

= 3 × 427

= 1281 Rs

S.P = 6144+1281

= 7425 Rs

∴ C.P < S.P

gain = 7425 – 6750

= 675

gain % = 675/6750 × 100

= 10%

Question no – (9)

Solution :

C.P of 25 kg = 25 × 7

= 175 Rs

C.P of 15 kg = 15 × 8

= 120 Rs

Total C.P= 175+120

= 295

p% = 22%

profit = 122×295/100

= 359.9

= 360

Rate = 360/(25+15)

= 360/40

= 9 rs per kg

Question no – (10)

Solution :

C.P of 1 dozen

= 45 rs

C.P of 2 dozen

= 45 × 2 = 90 rs

Gain % = 10%

S.P of 2 dozen

= 110/100

90 = 99 Rs

Total orange,

= 2 dozen

= 2 × 12

= 24

C.P of 1 orange = 45/24

Orange without rotten

= (24-13)

= 11 orange

S.P of without orange

= 99/11

= 9 Rs

Question no – (12)

Solution :

S.P = 240 rs

Let, C.P = 100

loss = 1/4 × 100

= 25 Rs

∴ C.P = 240+25

= 265 Rs

now, S.P = 360 Rs

C.P = 265 Rs

profit = 360 – 265

= 95 Rs

profit% = 100 × 95/265

= 35.84 %

Commercial Mathematics Exercise 8.4 Solution :

Question no – (1)

Solution :

(a) S.I = prt/100

= 7200 × 7.5 ×6/100×12

= 270 Rs

(b) S.I = prt/100

= 9000 × 8 × 5 / 100 × 20

= 1800 Rs

Question no – (2)

Solution :

(a) R = S.I×100/TP

= 975×100 / 5/2× 5200

= 975×2 / 8×52= 15/2

=7.5%

(b) ST = A – P

= 4734 – 3600

= 1134 RS

T = 3Y6 M = 7/2 Y

R = S.I × 100/PT

= 1134 × 100×2 / 3600×7

= 9%

Question no – (3)

Solution :

(a) T = S.I × 100 / PR

= 876×100 / 6×3650

= 8760 / 6×365

= 4 year

(b) A = 6720 – 1120

= 5600 Rs

T = S.I × 100 / PR

= 1120×100 / 5600×8

= 20/8

= 5/2 Y.

= 2y 6m.

Question no – (5)

Solution :

S.I = PRT/100

= 300000×7×15 / 100×2

= 157500 Rs

A = 157500+3300000

= 457500 Rs

Question no – (6)

Solution :

Let, P = x Rs

A = 2x Rs

R = 12%

S.I = 2x – x

= x Rs

S.I = 2x – x

= x Rs

S.I = PRT / 100

Or, T = S.I × 100 / PR

= x × 100 / x × 12

= 25/3 y

Question no – (7)

Solution :

R = S.I×100 / PT

= 560×100 / 28000×2

= 1%

Question no – (8)

Solution :

P = 18000 Rs ,

R = 15%,

T = 3Y6M

= 7/2 Y

S.I = prt/100

= 18000×15×7 / 100×2

= 9450 Rs

A = S.I + P

= 9450+18000

= 27,450 Rs

Total cash = 15000 + motorbike

motor bike = 274500 – 15000

= 12,450 Rs

* advantage → increase money.

Disadvantage → extra money to pay .

Question no – (9)

Solution :

P = ST×100 / TR

= 216×100 / 12×3

= 600 RS

Question no – (10)

Solution :

S.I = A – P

= 11,000 – 10000

= 1000 RS

T = 2

P = 10,000

R = ST × 100/PT

= 1000×100/10000×2

= 5%

Previous Chapter Solution :

Updated: May 27, 2023 — 6:56 am