ML AGGARWAL CLASS 7 Chapter 7 Percentage and Its Applications EXERCISE 7.3

  EXERCISE 7.3

Question 1

Cost price =Rs 60, selling price =₹ 874

Profit = Selling price - cost price 

= 8 74- 760

= Rs 114

profit percentage = $\left(\frac{p r of i t}{c \cdot p} \times 100\right) \%$

$=\left(\frac{114}{760} \times 100\right) \%$

=15 %

Question 2

Cost price =Rs 2500 ; selling price = Rs 2300

Loss $=$ cost price - selling price

= Rs 2500- Rs 2300

= Rs 200

Loss percent = ($\frac{\text { Loss }}{\text { C.P }} \times 100$)

$\begin{aligned}=&\left(\frac{200}{2500} \times 100\right) \cdot \% \\=8 \% . \end{aligned}$


Question 3

i) Cost price = Rs 250 ; Selling price = Rs 325

As S.p >C.P , Profit = S.P - C.p 

=325-250

=Rs 75 

profit percent $=\left(\frac{\text { profit }}{c \cdot p} \times 100\right) \%$

$=\left(\frac{75}{250} \times 100\right) \% .$

$=30 \%$

ii) Cost price = Rs 250 , Selling price = Rs 150

As C.P >S.P , Loss = C.P -S.P

=250- 150

= Rs 100

Loss percent $\left.=\frac{\text { Loss }}{C \cdot \rho} \times 100\right) \%$.

$=\left(\frac{100}{250} \times 100\right) \%$

$=40 \%$

Question 4

1st offer :

Cost price = Rs 4800

Profit = $13 \frac{1}{3} \%$ of Cost price = $\frac{40}{3} \times \frac{1}{100} \times 4800$

=640

Selling price = 480+ 640 i.e Cost price +profit = Rs 25440

2nd offer: 

Cost price = Rs 3640

Loss = 15 % of cost price = $=\frac{15}{100} \times 3640$

=Rs 546

$\begin{aligned} \text { Selling price } &=\text { cost price - Loss } \\ &=3640-546 \\ &= 3094 rs. \end{aligned}$

Selling price of 1st and 2nd offer = 5440+ 3094

= Rs 8440

As S.P > C.P , He always get gain 

i.e Gain = S.P - C.P

= 8534- 8440

= Rs 94

Question 5

cost price of 24 Tables $=24 \times 450$

= Rs 10,800

$\begin{aligned} \text { Selling price of } 16 \text { of them } &=16 \times 600 \\ &=9600 \end{aligned}$

Remaining i.e 24-16 =8 were sold 

i.e now s.p of 8 tables = 8 $\times $ 400

= 3200

∴ Total selling price = 9600+ 3200

= 1,2800

As S.P > C.P there is always a gain 

Gain = S.p - C.P 

12,800- 10,800

= Rs 2000

Question 6

Selling price = Rs 810 ;$ profit =Rs 60 

$\begin{aligned} \text { As } \text { profit } &=S \cdot p-c \cdot p \\ c \cdot p &=s \cdot p-\text { profit } \\ &=810-60 \end{aligned}$

Cost price =Rs 750

$\begin{aligned} \text { profit percent } &=\left(\frac{\text { profit }}{c \cdot p} \times 100\right) \% \\ &=\left(\frac{60}{750} \times 100\right) \% \\ &=8 \% \end{aligned}$

Question 7

Selling price -= Rs 3906; Loss = Rs 294

$\begin{aligned} \text { Loss }=&C \cdot p-s \cdot p\\ c \cdot p &=\text { Loss }+S \cdot p \\ &=294+3906 \\ &=4,200 . \end{aligned}$

Loss percent = $\left(\frac{\operatorname{loss} }{C.p} \times 100\right) \%$

$=\left(\frac{294}{4,200} \times 100\right) \%$

$=7 \%$

Question 8

C .P=Rs120, Loss percent =10%

Loss pescent $=\frac{\text { Loss }}{\text { c.p }} \times 100$

$\begin{aligned} \text { Loss } &=\frac{\text { Loss percent } c.p}{100} \\ &=\frac{10 \times 120}{100}=₹12\end{aligned}$

$\begin{aligned} \text { Loss }=& C \cdot p-s \cdot p \\ S \cdot p=&c\cdot p-\text { Loss }\\ &=120-12 \\ &=\ ₹108 \end{aligned}$

Question 9

cost price $=₹ 10,000 ;$ profit $=20 \%$

profit $\%=\frac{\text { Profit }}{C \cdot p} \times 100$

$20=\frac{\text { profit }}{10,000} \times 100$

profit $=\frac{20 \times 10,000}{10}$

profit $=20,00$

As profit = S.P - C.P

S.P =Profit + C.P 

= 2000+ 10,000

S.P = Rs 12,000

∴ Selling price = Rs 12,000

Question 10

selling price =Rs 300; profit $=20 \%$

profit percentage $=\left(\frac{\text { profit }}{\text { c.p }} \times 100\right) \%$.

$=\left(\frac{S \cdot p-C\cdot p}{C \cdot p} \times 100\right) \%$

$=\left[\frac{s \cdot p}{c \cdot p}-1\right] \times 100$

$20=\left(\frac{300}{c \cdot p}-1\right) \times 100$

$\frac{300}{c \cdot p}-1=\frac{20}{100}$

$\cdot \frac{300}{c \cdot p}-1=\frac{1}{5}$

$\frac{300}{C \cdot p}=1+\frac{1}{5}=\frac{6}{5}$

$\frac{300}{C \cdot p}=\frac{6}{5}$

$C \cdot P=\frac{300 \times 5}{6}$

$c \cdot$ P=Rs 250

$\therefore$ cost price =Rs 250 

Question 11

Selling price = Rs 320 ; Loss percent = 20 %

Loss percent = $\frac{\text { Loss }}{\text { c.p }} \times 100$

$=\frac{C p-s . p}{c \cdot p} \times 100$

$20=\left(1-\frac{320}{c \cdot p}\right) \times 100$

$1-\frac{320}{c \cdot p}=\frac{20}{100}$

$1-\frac{320}{c \cdot p}=\frac{1}{5}$

$\frac{320}{c \cdot p}=1 \frac{1}{5}$

$\frac{320}{6 \cdot p}=\frac{5-1}{5}$

$\frac{320}{c \cdot p}=\frac{4}{5}$

$c \cdot p=\frac{320 \times 5}{4}$

$c \cdot$ p=Rs 400

∴ Cost price = Rs 400

Question 12

selling price = Rs 522 ; profite 16%

profit $\%=\left(\frac{\text { profit }}{c \cdot p} \times 100\right)$

$=\frac{S \cdot p-c \cdot p}{C.p} \times 100$

$=\left(\frac{s \cdot p}{c \cdot p}-1\right) \times 100$

$16=\left(\frac{522}{c . p}-1\right) \times 100$

$\frac{522}{c.p}-1=\frac{16}{10}$

$\frac{522}{c \cdot p}-1=\frac{4}{25}$

$\frac{522}{c \cdot p}=1+\frac{4}{25}$

$\frac{522}{c \cdot p}=\frac{29}{25}$

$C \cdot p=\frac{522 \times 25}{29}$

$C \cdot$ p=Rs 750

$\therefore$ cost price =Rs 70

Question 13

selling price $=57360$; Loss $\%=8 \%$

$\begin{aligned} \text { Loss pescent } &=\left(\frac{\text { Loss }}{\text { c.p }} \times 100\right) \% \\ & \left.=\frac{C \cdot p-s \cdot p}{C \cdot p} \times 100\right) \end{aligned}$

$=\left(1-\frac{s \cdot p}{c \cdot p}\right) \times 100$

$8=\left(1-\frac{\partial 360}{c \cdot p}\right) \times 1$

$\frac{8}{100}=1-\frac{7360}{c. p}$

$\frac{2}{25}=1=\frac{7360}{c .p}$

$\frac{7360}{c p}=1-\frac{2}{25}$

$\frac{7360}{c \cdot p}=\frac{23}{25}$

$c.{p}=\frac{7360 \times 25}{23}$

$c \cdot$ p=Rs 8,000

cost price =Rs 8000

Question 14

Selling price= Rs 3168 ; Loss = $12 \%$

Loss percentage $=\frac{\text { Loss }}{C \cdot p} \times 100$

$=\left[1-\frac{S \cdot p}{C \cdot p}\right] \times 100$

$12=\left[1-\frac{3168}{c.p}\right] \times 100$

$1-\frac{3168}{6.8}=\frac{12}{100}$

$1-\frac{3168}{c\cdot p}=\frac{3}{25}$

$\frac{3168}{6 . p}=1-\frac{3}{25}$

$\frac{3168}{c. p}=\frac{22}{25}$

$c \cdot p=\frac{3168 \times 25}{23}$

C.p =Rs 3600

Given selling price = 3870

As S.P > C.P he gains 

So gain = S.P - C.P = 3870-3600

= 270

Gain percentage = ($\frac{\text { Gain }}{\text { c.p }} \times 100$)%

$=\left(\frac{270}{3600} \times 100\right) \%$

=75 %

Question 15

selling price =Rs4550, Loss =9 %

Loss percent $=\left[1-\frac{S \cdot p}{C.p}\right] \times 100$

$9=\left[1-\frac{4550}{c \cdot p}\right] \times 100$

$1-\frac{4550}{c \cdot p}=\frac{9}{100}$

$\frac{4550}{c \cdot p}=1-\frac{9}{100}$

$\frac{4550}{c \cdot p}=\frac{91}{100}$

$c \cdot p=\frac{4550 \times 100}{91}$

$C \cdot$ p=Rs 5000

As given selling price = 4825

As C.P > S.P, so he lose 

Loss = C.P - S.P

= 5000- 4825

Loss = Rs 175

Loss percent =  ($\frac{\text { Loss }}{c. p} \times 100$)

$=\left(\frac{175}{5000} \times 100\right)$

=3.5 %

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