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Chapter 10

Profit, Loss and Discount — Exercise 10(A)

Class - 7 Concise Mathematics Selina



Exercise 10(A)

Question 1(i)

Find the gain or loss percent, if:

C.P. = ₹ 200 and S.P. = ₹ 224

Answer

C.P. = ₹ 200 and S.P. = ₹ 224

Since S.P. > C.P., there is a gain.

Gain = S.P. − C.P. = 224 − 200 = ₹ 24.

Gain% = (gainC.P.×100)\left(\dfrac{\text{gain}}{\text{C.P.}} \times 100\right)%

= (24200×100)\left(\dfrac{24}{200} \times 100\right)%

= 2,400200\dfrac{2,400}{200}%

= 12%

Hence, the gain percent is 12%.

Question 1(ii)

Find the gain or loss percent, if:

C.P. = ₹ 450 and S.P. = ₹ 400

Answer

C.P. = ₹ 450 and S.P. = ₹ 400

Since C.P. > S.P., there is a loss.

Loss = C.P. − S.P. = 450 − 400 = ₹ 50.

Loss% = (lossC.P.×100)\left(\dfrac{\text{loss}}{\text{C.P.}} \times 100\right)%

= (50450×100)\left(\dfrac{50}{450} \times 100\right)%

= 5,000450\dfrac{5,000}{450}%

= 1009\dfrac{100}{9}%

= 111911\dfrac{1}{9}%

Hence, the loss percent is 111911\dfrac{1}{9}%.

Question 1(iii)

Find the gain or loss percent, if:

C.P. = ₹ 550 and gain = ₹ 22

Answer

C.P. = ₹ 550 and gain = ₹ 22

Gain% = (gainC.P.×100)\left(\dfrac{\text{gain}}{\text{C.P.}} \times 100\right)%

= (22550×100)\left(\dfrac{22}{550} \times 100\right)%

= 2,200550\dfrac{2,200}{550}%

= 4%

Hence, the gain percent is 4%.

Question 1(iv)

Find the gain or loss percent, if:

C.P. = ₹ 216 and loss = ₹ 72

Answer

C.P. = ₹ 216 and loss = ₹ 72

Loss% = (lossC.P.×100)\left(\dfrac{\text{loss}}{\text{C.P.}} \times 100\right)%

= (72216×100)\left(\dfrac{72}{216} \times 100\right)%

= 7,200216\dfrac{7,200}{216}%

= 1003\dfrac{100}{3}%

= 331333\dfrac{1}{3}%

Hence, the loss percent is 331333\dfrac{1}{3}%.

Question 1(v)

Find the gain or loss percent, if:

S.P. = ₹ 500 and loss = ₹ 100

Answer

S.P. = ₹ 500 and loss = ₹ 100

C.P. = S.P. + loss = 500 + 100 = ₹ 600.

Loss% = (lossC.P.×100)\left(\dfrac{\text{loss}}{\text{C.P.}} \times 100\right)%

= (100600×100)\left(\dfrac{100}{600} \times 100\right)%

= 10,000600\dfrac{10,000}{600}%

= 503\dfrac{50}{3}%

= 162316\dfrac{2}{3}%

Hence, the loss percent is 162316\dfrac{2}{3}%.

Question 2(i)

Find the selling price, if:

C.P. = ₹ 500 and gain = 25%

Answer

C.P. = ₹ 500 and gain = 25%

S.P. = C.P. ×(1+gain percentage100)\times \left(1 + \dfrac{\text{gain percentage}}{100}\right)

=500×(1+25100)=500×125100=₹ 625= 500 \times \left(1 + \dfrac{25}{100}\right)\\[1em] = 500 \times \dfrac{125}{100}\\[1em] = ₹\ 625

Hence, the selling price of the article is ₹ 625.

Question 2(ii)

Find the selling price, if:

C.P. = ₹ 60 and loss = 121212\dfrac{1}{2}%

Answer

C.P. = ₹ 60 and loss = 121212\dfrac{1}{2}%

As, 121212\dfrac{1}{2}% =252= \dfrac{25}{2}%

S.P. = C.P. ×(1loss percentage100)\times \left(1 - \dfrac{\text{loss percentage}}{100}\right)

=60×(125200)=60×175200=₹ 52.50= 60 \times \left(1 - \dfrac{25}{200}\right)\\[1em] = 60 \times \dfrac{175}{200}\\[1em] = ₹\ 52.50

Hence, the selling price of the article is ₹ 52.50.

Question 3

Rohit bought a tape recorder for ₹ 1,500 and sold it for ₹ 1,800. Calculate his profit or loss percent.

Answer

C.P. = ₹ 1,500 and S.P. = ₹ 1,800.

Since S.P. > C.P., there is a profit.

Profit = 1,800 − 1,500 = ₹ 300.

Profit% = (profitC.P.×100)\left(\dfrac{\text{profit}}{\text{C.P.}} \times 100\right)%

= (3001,500×100)\left(\dfrac{300}{1,500} \times 100\right)%

= 30,0001,500\dfrac{30,000}{1,500}%

= 20%

Hence, Rohit made a profit of 20%.

Question 4

An article bought for ₹ 350 is sold at a profit of 20%. Find its selling price.

Answer

C.P. = ₹ 350 and profit = 20%.

S.P. = C.P. ×(1+profit percentage100)\times \left(1 + \dfrac{\text{profit percentage}}{100}\right)

=350×120100=42,000100=₹ 420= 350 \times \dfrac{120}{100}\\[1em] = \dfrac{42,000}{100}\\[1em] = ₹\ 420

Hence, the selling price of the article is ₹ 420.

Question 5

An old machine is bought for ₹ 1,400 and is sold at a loss of 15%. Find its selling price.

Answer

C.P. = ₹ 1,400 and loss = 15%.

S.P. = C.P. ×(1loss percentage100)\times \left(1 - \dfrac{\text{loss percentage}}{100}\right)

=1,400×85100=1,19,000100=₹ 1,190= 1,400 \times \dfrac{85}{100}\\[1em] = \dfrac{1,19,000}{100}\\[1em] = ₹\ 1,190

Hence, the selling price of the machine is ₹ 1,190.

Question 6

Oranges are bought at 5 for ₹ 10 and sold at 6 for ₹ 15. Find profit or loss as percent.

Answer

C.P. of 1 orange = 105\dfrac{10}{5} = ₹ 2.

S.P. of 1 orange = 156\dfrac{15}{6} = ₹ 2.50.

Since S.P. > C.P., there is a profit.

Profit on 1 orange = 2.50 − 2 = ₹ 0.50.

Profit% = (profitC.P.×100)\left(\dfrac{\text{profit}}{\text{C.P.}} \times 100\right)%

= (0.502×100)\left(\dfrac{0.50}{2} \times 100\right)%

= 502\dfrac{50}{2}%

= 25%

Hence, the profit percent is 25%.

Question 7

A certain number of articles are bought at 3 for ₹ 150 and all of them are sold at 4 for ₹ 180. Find the loss or gain as percent.

Answer

C.P. of 1 article = 1503\dfrac{150}{3} = ₹ 50.

S.P. of 1 article = 1804\dfrac{180}{4} = ₹ 45.

Since C.P. > S.P., there is a loss.

Loss on 1 article = 50 − 45 = ₹ 5.

Loss% = (lossC.P.×100)\left(\dfrac{\text{loss}}{\text{C.P.}} \times 100\right)%

= (550×100)\left(\dfrac{5}{50} \times 100\right)%

= 50050\dfrac{500}{50}%

= 10%

Hence, the loss percent is 10%.

Question 8

A vendor bought 120 sweets at 20 p each. In his house, 18 were consumed and he sold the remaining at 30 p each. Find his profit or loss as percent.

Answer

Total C.P. = 120 × 20 p = 2,400 p = ₹ 24.

Number of sweets sold = 120 − 18 = 102.

Total S.P. = 102 × 30 p = 3,060 p = ₹ 30.60.

Since S.P. > C.P., there is a profit.

Profit = 30.60 − 24 = ₹ 6.60.

Profit% = (profitC.P.×100)\left(\dfrac{\text{profit}}{\text{C.P.}} \times 100\right)%

= (6.6024×100)\left(\dfrac{6.60}{24} \times 100\right)%

= 66024\dfrac{660}{24}%

= 27.5%

Hence, the profit percent is 27.5%.

Question 9

The cost price of an article is ₹ 1,200 and selling price is 54\dfrac{5}{4} times of its cost price. Find:

(i) selling price of the article,

(ii) profit or loss as percent.

Answer

C.P. = ₹ 1,200 and S.P. = 54\dfrac{5}{4} times of C.P.

(i) S.P. = 54×1,200\dfrac{5}{4} \times 1,200

= 6,0004\dfrac{6,000}{4}

= ₹ 1,500

Hence, the selling price of the article is ₹ 1,500.

(ii) Since S.P. > C.P., there is a profit.

Profit = 1,500 − 1,200 = ₹ 300.

Profit% = (profitC.P.×100)\left(\dfrac{\text{profit}}{\text{C.P.}} \times 100\right)%

= (3001,200×100)\left(\dfrac{300}{1,200} \times 100\right)%

= 30,0001,200\dfrac{30,000}{1,200}%

= 25%

Hence, the profit percent is 25%.

Question 10

The selling price of an article is ₹ 1,200 and cost price is 54\dfrac{5}{4} times of its selling price. Find:

(i) cost price of the article,

(ii) profit or loss as percent.

Answer

S.P. = ₹ 1,200 and C.P. = 54\dfrac{5}{4} times of S.P.

(i) C.P. = 54×1,200\dfrac{5}{4} \times 1,200

= 6,0004\dfrac{6,000}{4}

= ₹ 1,500

Hence, the cost price of the article is ₹ 1,500.

(ii) Since C.P. > S.P., there is a loss.

Loss = 1,500 − 1,200 = ₹ 300.

Loss% = (lossC.P.×100)\left(\dfrac{\text{loss}}{\text{C.P.}} \times 100\right)%

= (3001,500×100)\left(\dfrac{300}{1,500} \times 100\right)%

= 30,0001,500\dfrac{30,000}{1,500}%

= 20%

Hence, the loss percent is 20%.

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