Students can Download Maths Chapter 9 Commercial Arithmetic Ex 9.2 Questions and Answers, Notes Pdf, KSEEB Solutions for Class 8 Maths helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.

## Karnataka Board Class 8 Maths Chapter 9 Commercial Arithmetic Ex 9.2

Question 1.

Sonu bought a bicycle for Rs. 3750 and spent Rs. 250 on its repairs. He sold it for Rs. 4400. Find his loss or profit percentage.

Answer:

C.P = 3750 + 250 = Rs. 4000 S P = Rs. 4400

S.P > C.P

∴ S.P – C.P = 4400 – 4000 = Rs. 400

Protit percent = × 100

= × 100 = 10

Profit percent = 10%

Question 2.

A shop keeper purchases an article for Rs. 3500 and pays the transport charge of Rs. 100. He incurred a loss of 12% in selling this. Find selling price of the article.

Answer:

C.P = 3500 + 100 = Rs. 3600

Loss percent = 12%

S.P = Rs.3168.

Question 3.

By selling a watch for Rs. 720, Ravi loses 10%. At what price should he sell it, in order to gain 15% .

Answer:

S.P = Rs. 720,

loss percent = 10% C.P = ?

\(\begin{aligned} \mathrm{CP} &=\frac{100}{(100-\text { Loss percent })} \times \mathrm{SP} \\ &=\frac{100}{(100-10)} \times 720=\frac{100}{90} \times 720 \end{aligned}\)

C.P = RS. 800

gain percent = 15 %

S.P = ?

\(\begin{aligned} \mathrm{S.P} &=\frac{(100+\mathrm{gain} \%)}{100} \times \mathrm{C.P} \\ &=\frac{100+15}{100} \times 800=\frac{115}{100} \times 800 \end{aligned}\)

S.P = Rs. 920

He should sell it for Rs. 920 to gain a 15% profit.

Question 4.

Hari bought two fans for Rs. 2400 each. He sold one at a loss of 10% and the other at a profit of 15%. Find the selling price of each fan and also the total profit or loss.

Answer:

C.P = Rs. 2400, Loss% = 10%

S.P = ?

S.P = Rs. 2160

∴ When the loss percent is 10% S.P. is Rs. 2160

C.P = Rs. 2400

profit percent = 15%

S.P = ?

\(\begin{aligned} \mathrm{S.P} &=\frac{(100+\text { Profit } \%)}{100} \times \mathrm{C.P} \\ &=\frac{100+15}{100} \times 2400=\frac{115}{100} \times 2400 \end{aligned}\)

S.P. = Rs. 2760.

When the profit percent is 15%, the S.P. is Rs. 2760.

Total C.P. of two fans is 2400 + 2400 = Rs. 4800.

Total S.P. of two fans is 2160 + 2760 = Rs. 4920.

Total SP > Total C.P

∴ Total profit = Total S.P – Total C.P = 4920-4800 Profit = Rs. 120.

Question 5.

A storekeeper sells a book at a 15% gain. Had he sold it for Rs. 18 more. He would have gained 18%. Find the cost price of the book.

Answer:

Let the C.P be Rs. x

gain % = 15%

Had he sold it for Rs. 18 more the new S.P.

would be Rs. \(\frac{115 x}{100}\) . This is equal to S.P

When the gain percent is 18%

S.P when gain percent is 18% is

118 x – 115 x = 1800

3 x = 1800

x = \(\frac { 1800 }{ 3 }\)

x = 600

∴ Cost price = Rs.600.

Question 6.

The cost price of 12 pens is equal to the selling price of 10 pens. Find the profit percentage.

Answer:

Let the C.P of one pen be Rs. 1

∴ C.P of 12 pens = Rs. 12

Given S.P. of 10 pens = C.P. of 12 pens.

S.P. of 10 pens = Rs. 12 C.P of 10 pens = Rs. 10

∴ S.P > C.P So there is gain

Gain = S.P – C.P= 12 – 10 = 2

Gain percent = \(\frac { Gain }{ C.P }\) × 100

= \(\frac { 2 }{ 10 }\) × 100 = 20 %

Gain percent = 20%