# Exercise 8.3 - Chapter 8 Comparing Quantities class 7 ncert solutions Maths - SaraNextGen [2024]

Question 1:

Tell what is the profit or loss in the following transactions. Also find profit

percent or loss percent in each case.

(a) Gardening shears bought for Rs 250 and sold for Rs 325.

(b) A refrigerator bought for Rs 12,000 and sold at Rs 13,500.

(c) A cupboard bought for Rs 2,500 and sold at Rs 3,000.

(d) A skirt bought for Rs 250 and sold at Rs 150.

(a) Cost price = Rs 250

Selling price = Rs 325

Profit = 325 − 250 = Rs 75

= = 30%

(b) Cost price = Rs 12000

Selling price = Rs 13,500

Profit = 13500 − 12000 = Rs 1500

Profit % =  = 12.5%

(c) Cost price = Rs 2500

Selling price = Rs 3000

Profit = 3000 − 2500 = Rs 500

Profit % = = 20%

(d) Cost price = Rs 250

Selling price = Rs 150

Loss = 250 − 150 = Rs 100

Loss % =  = 40%

Question 2:

Convert each part of the ratio to percentage:

(a) 3:1 (b) 2:3:5 (c) 1:4 (d) 1:2:5

(a) 3: 1

Total parts = 3 + 1 = 4

1st part

2nd part =

(b) 2: 3: 5

Total parts = 2 + 3 + 5 = 10

1st part =

2nd part =

3rd part =

(c) 1: 4

Total parts =1 + 4 = 5

1st part =

2nd part =

(d) 1: 2: 5

Total parts = 1 + 2 + 5 = 8

1st part =

2nd part =

3rd =

Question 3:

The population of a city decreased from 25,000 to 24,500. Find the percentage decrease.

Initial population = 25000

Final population = 24500

Decrease = 500

% decrease =

Question 4:

Arun bought a car for Rs 3,50,000. The next year, the price went upto

Rs 3,70,000. What was the percentage of price increase?

Initial price = Rs 350000

Final price = Rs 370000

Increase = Rs 20000

% increase =

%

Question 5:

I buy a T.V. for Rs 10,000 and sell it at a profit of 20%. How much money do I get for it?

Cost price = Rs 10000

Profit = 20% of 10000

= Rs 2000

Selling price = Cost price + Profit

= 10000 + 2000 = Rs 12,000

Question 6:

Juhi sells a washing machine for Rs 13, 500. She loses 20% in the bargain. What was the price at which she bought it?

Selling price = Rs 13500

Loss % = 20%

Let the cost price be x.

∴ Loss = 20% of x

Cost price − Loss = Selling price

= 16875

Therefore, she bought it for Rs 16875.

Question 7:

(i) Chalk contains calcium, carbon and oxygen in the ratio 10:3:12. Find the percentage of carbon in chalk.

(ii) If in a stick of chalk, carbon is 3g, what is the weight of the chalk stick?

(i) Ratio of calcium, carbon, and oxygen = 10: 3: 12

As 10 + 3 +12 = 25,

Therefore, percentage of carbon =  = 12%

(ii) Let the weight of the stick be x g.

12 % of x = 3

Question 8:

Amina buys a book for Rs 275 and sells it at a loss of 15%. How much does she sell it for?

Cost price = Rs 275

Loss % = 15%

Loss = 15% of 275

Cost price − Loss = Selling price

275 − 41.25 = Selling price

Selling price = Rs 233.75

Question 9:

Find the amount to be paid at the end of 3 years in each case:

(a) Principal = Rs 1,200 at 12% p.a.

(b) Principal = Rs 7,500 at 5% p.a.

(a) Principal (P) = Rs 1200

Rate (R) = 12 % p.a.

Time (T) = 3 years

= Rs 432

Amount = P + S.I.

= 1200 + 432

= Rs 1632

(b) P = Rs 7500

R = 5% p.a.

T = 3 years

= Rs 1125

Amount = 7500 + 1125

= Rs 8625

Question 10:

What rate gives Rs 280 as interest on a sum of Rs 56,000 in 2 years?

Therefore, 0.25% gives Rs 280 as interest on the given sum.

Question 11:

If Meena gives an interest of Rs 45 for one year at 9% rate p.a.. What is the sum she has borrowed?