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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 :**

Nambar of cadefs

= 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_{2 }

= 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 :**