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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 towster2
= 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 :
please add recap exercise