SChand Composite Mathematics Class 7 Chapter 9 Percentage and it's application Exercise 9D

  Exercise 9D 

Question 1 

A man bought an article for Rs 25 and sold it far Rs 40 . Another man bought an article for Rs 50 and sod it far Rs 65 . What rate of profit is greater and by what percent ? 

Sol: C.P of 1st man = Rs 25 

S.P -------------= Rs 40; Profit = 40 - 25 = Rs 15

Profit %  = $\frac{15}{25} \times 100=60 \%$

C.P of 2nd man = Rs 50 

S.P = Rs 65; Profit = 65-50 = 15 

Profit % = $\frac{15}{50} \times 100$ = 30% 

Profit of first man is greater and by 60-30 = 30 % answer 

Question 2

Sameer bought 1600 bananas at Rs 3.75 a dozen. He sold 900 of them at 2 far Rs 1 and the remaining at 5 far Rs 2 . find his gain or loss % 

Sol: C.P of 1600 bananas are = 1600 $\times 3.75$

= Rs $\frac{6.000}{12}=Rs500$

S.P OF 900 Bananas 3 for Rs 1 = $450 \times =Rs 450$

 

Remaining 700 bananas 5 for Rs 2 = $\frac{700}{5} \times 2=₹ 280$

S.P = 450 + 280 = Rs 730

Gain = 730 - 500 = 230

Gain% = $\frac{230}{500} \times 100=46 \%$

Question 3

A woman bought 50 dozen eggs at Rs 169 dozen, out of these , 30 eggs were found to Rs 1.50 per egg. Find her gain or loss % 

Sol: 50 dozen = $50 \times 12=600$ eggs

$C \cdot P \cdot=50 \times 16=Rs 800$

Remaining eggs after broken = 600-20= 580

S.P = $580 \times 1.50=Rs 870$

Profit = 870 - 800= Rs 70

Gain % = $\frac{70}{800} \times 100=8.75 \%$

Question 4

Peter bought an article for Rs 1215 and spent Rs 35 on its transportation . At what price should be sell the article to gain 16% ? 

Sol: C.P = 1215 ; Spent= Rs 35 

E.C.P = 1215 + 35 = Rs 1250 

Gain = 16% of 1250= $\frac{16}{100} \times 1250$

Gain = Rs 200

Selling price = C.P + GAIN 

$=1250+200$

$=21450$ Ans

Question 5

By selling a chair far Rs 30 , a dealer makes a profit of 25 % . Find what price did the dealer pay far it? 

Sol: S.P of chair = Rs 30; Let C.P = x 

Profit = 25% Of x = $\frac{25}{100} \times x=\frac{x}{4}$

S.P. $=x+\frac{x}{4}=\frac{4 x+x}{4}=\frac{5 x}{4}$

$\therefore \quad \frac{5x}{4}=30$ =  $x=30 \times \frac{4}{5}$

C.P = Rs 24 Ans 

Question 6

Sarita bought eggs at Rs 8.40 a dozen . AT what price per hundred must she sell them so as to earn a profit of 15 % 

Sol: Cost prize of dozen eggs =  Rs 8.40 

C.P of 1 egg = $\frac{8.40}{12}=Rs 0.70$

Gain = 15% of 70 

 

$=\frac{15}{100} \times 70$ = $\frac{21}{2}=Rs 10.5$

S.P = C.P + Gain 

$70+10.5=Rs 80.5$

Question 7

If the C.P of 6 articles is equal to the S.P of 4 articles find the gain percent. 

Sol: C.P $\times 6=4 \times S . P$ 

$\frac{c \cdot p}{s \cdot p}=\frac{4}{6} \Rightarrow$ S.P. $-C \cdot p \cdot=6-4=2$

gain $\%=\frac{2}{4} \times 100=50 \%$

Question 8

A man buys toffees at 10 for Rs 3 and sells them at 8 far Rs 3 ; find his gain ? 

Sol: Buys 10 toffees far Rs 3 

1 toffee = $\frac{3}{10}$

S.P Of 8 Rs 3

S.P of 1 = $\frac{3}{8}$

gain $=\frac{3}{8}-\frac{3}{10}=\frac{15-12}{40}=\frac{3}{40}$

Gain % = $\frac{\text { gain }}{C .P } \times 100=\frac{\frac{3}{40}}{\frac{3}{10}} \times 100$

$\frac{3}{40} \times \frac{10}{3} \times 100=25 \%$

Question 9

A man sold two paintings at Rs 924 Each . On one he gain 20 % and on the other he loses 20 % . How much does he  gain or loss in the whole transaction ? 

Sol: S.P of one painting = Rs 924

Let C.P =x 

Gain = 20% Of x = $-\frac{20}{100} \times x=\frac{x}{5}$

S.P = $x+\frac{x}{5}=\frac{5 x+x}{5}=\frac{6 x}{5}$

= $\frac{6 x}{5}=924 \Rightarrow x=$ $924 \times \frac{5}{6}=Rs 770$

C.P OF 1st painting = Rs 770 

Let C.P of 2nd painting = y 

Loss = 20 % of Y= $\frac{20}{100} \times y=\frac{y}{5}$

S.P = y- $\frac{y}{5}=\frac{5 y-y}{5}=\frac{4 y}{5}$

$\because \frac{4 y}{5}=Rs 924$

$y=924 \times \frac{5}{4}=Rs 1155$

Overall S.P = $924+924=Rs 1848$

overall C.P = $770+1155=Rs 1925$

C.p. $>$ s.p. $\Rightarrow$ loss $=1925-1848$

= Rs 77 loss

Question 10

By selling a fan far Rs 1200 , Karim losses Rs 200 AT what  prize must he sell it to gain 10 % . 

Sol: S.P Of Fan = Rs 1200

Loss = Rs 200  = C.P = S.P + LOSS 

1200 +200 = Rs 1400

Gain = 10% of 1400= $\frac{10}{100} \times 1400=140$

S.P Of Gain = 1400+ 140 = Rs 1540 answer 

Question 11

A shopkeeper buys Rs 50 per Ream . At what price per quire should he sell it to gain 20 % ? 

Sol: Cost of 1 Ream = Rs 50

Cost of 20 quires = Rs 50 

Cost of 1 quires =$\frac{50}{20}=Rs 2.5$

To get gain of 205 On per quires 

20% of 2.5

$\frac{20}{100} \times \frac{2.5}{10}$ = Rs 0.50

To get gain S.P = C.P + Gain

$=2.5+0.5$

$=Rs 3.0$ Ans