NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3
These NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 Questions and Answers are prepared by our highly skilled subject experts.
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Exercise 8.3
Question 1.
Tell what is the profit or loss in the following transactions. Also find profit per cent or loss per cent ¡n each case,
(a) Gardening shears bought for 250 and sold for ₹ 325 .
(b) A refrigerator bought for ₹ 12,000 and sold at 13,500.
(c) A cupboard bought for ₹ 2,500 and sold at 3,000.
(d) A skirt bought for ₹ 250 and sold at ₹ 150.
Answer:
(a) Cost Price (CP) = ₹ 250
Selling Price = ₹ 325
Profit = S.P – C.P
= ₹ 325 – 250
= ₹ 75
Profit% = 75/250 x 100%
= 3 x 100%
= 30%
Profit = ₹ 75; Profit % = 30%.
(b) Cost Price (CP) = ₹ 12,000
Selling Price (SP) = ₹ 13,500
Profit = SP – CP
= ₹ 13500 – ₹ 12000
= ₹ 1500
Profit = ₹ 1500 and Profit% = 12.5%.
(c) Cost Price (CP) = ₹ 2500
Selling Price (SP) = ₹ 3000
Profit = SP – CP
= ₹ 3000 – 2500
= ₹ 500
Profit = ₹ 500
and Profit% = 20%.
(d) Cost Price (CP) = ₹ 250
Selling Price (SP) = ₹ 150
Loss = CP – S.P
= ₹ 250 – 150
= ₹ 100
Question 2.
Convert each part of the ratio to percentage:
(a) 3 : 1
(b) 2 : 3 :5
(c) 1 : 4
(d) 1 : 2 : 5
Answer:
(a) 3:1
Total parts of the ratio = 3 + 1 = 4
(b) 2:3:5
Total parts of the ratio
= 2 + 3 + 5 = 10
(c) 1:4
Total parts of the ratio = 1+4 = 5
(d) 1:2:5
Total parts of the ratio = 1 + 2 + 5 = 8
Question 3.
The population of a city decreased from 25,000 to 24,500. Find the percentage decrease.
Answer:
Question 4.
Arun bought a car for ₹ 3,50,000. The next year, the price went upto ₹ 3,70,000. What was the percentage of price increase?
Answer:
Initial cost = ₹ 3,50,000
Increased cost = ₹ 3,70,000
Increase in price = ₹ 3,70,000 – 3,50,000
= ₹ 20,000
Question 5.
I buy a T.V. for ₹ 10,000 and sell it at a profit of 20%. How much money do I get for it?
Answer:
Selling price of the T.V = ₹ 10,000 + ₹ 2000 = ₹ 12,000
Hence, I get ₹ 12,000
Question 6.
Juhi sells a washing machine for ₹ 13,500. She loses 20% in the bargain. What was the price at which she bought it?
Answer:
Let the cost price of the washing machine be Y
Selling price of the washing machine = ₹ 13,500
She bought it for ₹ 16,875.
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 3 g, what is the weight of the chalk stick?
Answer:
(i) The ratio of calcium : carbon :
oxygen = 10 : 3 : 12
Total ratios = 10 + 3 + 12 = 25
Question 8.
Amina buys a book for ₹ 275 and sells it at a loss of 15%. How much does she sell it for?
Answer:
Cost price of the book = ₹ 275
Loss = 15% of C.P
S.P of the book = ₹ 233.75
= ₹ 41.25
Question 9.
Find the amount to be paid at the end of 3 years in each case:
(a) Principal = ₹ 1200 at 12% p.a.
(b) Principal = ₹ 7500 at 5% p.a.
Answer:
(a) Principal (P) = ₹ 1200
Amount = Principal + Interest
= ₹ 1200 + 432
= ₹ 1632
Amount to be paid at the end of 3 years = ₹ 1632
(b) Principal (P) = ₹ 7500
Amount to be paid = ₹ 8625
Question 10.
What rate gives ₹ 280 as interest on a sum of ₹ 56,000 is 2 years?
Answer:
Question 11.
If Meena gives an interest of ₹ 45 for one year at 9% rate p.a. What is the sum she has borrowed?
Answer:
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