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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 in 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.
Solution:
(a) Here, CP = ₹ 250
SP = ₹ 325
Since SP > CP
∴ Profit = SP – CP
= ₹ 325 – ₹ 250 = ₹ 75


Hence, the required profit = ₹ 75
and Profit per cent = 30%

(b) Here, CP = ₹ 12,000
SP = ₹ 13,500
Since SP > CP
∴ Profit = SP – CP
= ₹ 13,500 – ₹ 12,000 = ₹ 1,500


Hence, the required profit = ₹ 1500 × 100
profit % = 12%

(c) Here, CP = ₹ 2500
SP = ₹ 3000
Since SP > CP
∴ Profit = SP – CP
= ₹ 3000 – ₹ 2500 = ₹ 500


Hence, the required profit = ₹ 500 and profit% = 20%

(d) Here, CP = ₹ 250
SP = ₹ 150
Here CP > SP
∴ Loss = CP – SP
= ₹ 250 – ₹ 150 = ₹ 100


Hence, the required loss = ₹ 100 and 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
Solution:
(a) 3 : 1
Sum of the ratio parts = 3 + 1 = 4

(b) 2 : 3 : 5
Sum of the ratio parts = 2 + 3 + 5 = 10

(c) 1 : 4
Sum of the ratio parts =1 + 4 = 5

(d) 1 : 2 : 5
Sum of the ratio parts = 1 + 2 + 5 = 8

Question 5.
I buy a TV for ₹ 10,000 and sell it at a profit of 20%. How much money do I get for it?
Solution:
Here, CP = ₹ 10,000
Profit = 20%
SP = ?
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 10
Hence, the required money got by me = ₹ 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?
Solution:
SP of the washing machine = ₹ 13,500
Loss = 20%
CP = ?
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 11
Hence, the cost price of the machine = ₹ 16875.

Question 8.
Amina buys a book for ₹ 275 and sells it at a loss of 15%. How much does she sell it for?
Solution:
CP of book = ₹ 275
Loss = 15%
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 12
Hence, the required selling price = ₹ 233.75

Question 10.
What rate gives ₹ 280 as interest on a sum of ₹ 56,000 in 2 years?
Solution:
Given: Principal = ₹ 56,000
Interest = ₹280
Time = 2 years
Rate = ?


Hence, the required rate = 0.25%

Question 11.
If Meena gives an interest of ₹ 45 for one year at 9% rate p.a. What is the sum she has borrowed?
Solution:
Given: Interest = ₹ 45
Time = 1 year
Rate = 9% p.a.
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 14
Hence, the required sum = ₹ 500.

NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 Q1
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 Q2
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NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 Q5
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 Q6
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.3 Q7
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