Class 7 Maths
Comparing Quantities
Ex.8.1 Q.1
Find the ratio of:
(a) ₹5 to 50 paise
(b) 15 kg to 210 g
(c) 9 m to 27 cm
(d) 30 days to 36 hours
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Ex.8.1 Q.2
In a computer lab, there are 3 computers for every 6 students.
How many computers will be needed for 24 students?
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Ex.8.1 Q.3
Population of Rajasthan = 570 lakhs and population of U.P. = 1660 lakhs.
Area of Rajasthan = 3 lakh km2 and area of U.P. = 2 lakh km2.
(i) How many people are there per km2 in both states?
(ii) Which state is less populated?
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Ex.8.2 Q.1
Convert the given fractional numbers to percent:
(a)
(b)
(c)
(d)
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Ex.8.2 Q.2
Convert the given decimal fractions to per cents:
(a) 0.65
(b) 2.1
(c) 0.02
(d) 12.35
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Ex.8.2 Q.3
Estimate what part of the figures is coloured and hence find the percent which is coloured.
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Ex.8.2 Q.4
Find:
(a) 15% of 250
(b) 1% of 1 hour
(c) 20% of ₹2500
(d) 75% of 1 kg
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Ex.8.2 Q.5
Find the whole quantity if:
(a) 5% of it is 600
(b) 12% of it is ₹1080
(c) 40% of it is 500 km
(d) 70% of it is 14 minutes
(e) 8% of it is 40 litres
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Ex.8.2 Q.6
Convert given per cents to decimal fractions and also to fractions in simplest forms:
(a) 25%
(b) 150%
(c) 20%
(d) 5%
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Ex.8.2 Q.7
In a city, 30% are females, 40% are males and remaining are children. What percent are children?
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Ex.8.2 Q.8
Out of 15,000 voters in a constituency, 60% voted. Find the percentage of voters who did not vote.
Can you now find how many actually did not vote?
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Ex.8.2 Q.9
Meeta saves ₹ 400 from her salary. If this is 10% of her salary, what is her salary?
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Ex.8.2 Q.10
A local cricket team played 20 matches in one season. It won 25% of them.
How many matches did they win?
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Ex.8.3 Q.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 ₹ 250 and sold for ₹ 325.
(b) A refrigerator bought ₹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.
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Ex.8.3 Q.2
Convert each part of the ratio to percentage:
(a) 3 : 1
(b) 2 : 3 : 5
(c) 1 : 4
(d) 1 : 2 : 5
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Ex.8.3 Q.3
The population of a city decreased from 25,000 to 24,500. Find the percentage decrease.
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Ex.8.3 Q.4
Arun bought a car for ₹3,50,000. The next year, the price went up to ₹3,70,000.
What was the percentage of price increase?
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Ex.8.2 Q.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?
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Ex.8.3 Q.6
Juhi sells a washing machine for ₹13,500. She loses 20% in the bargain.
What was the price at which she bought it?
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Ex.8.3 Q.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?
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Ex.8.3 Q.8
Amina buys a book for ₹275 and sells it at a loss of 15%. How much does she sell it for?
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Ex.8.3 Q.9
Find the amount to be paid at the end of 3 years in each case:
(a) Principal = ₹1,200 at 12% p.a.
(b) Principal = ₹ 7,500 at 5% p.a.
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Ex.8.3 Q.10
What rate gives ₹ 280 as interest on a sum of ₹ 56,000 in 2 years?
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Ex.8.3 Q.11
If Meena gives an interest of ₹45 for one year at 9% rate p.a.
What is the sum she has borrowed?
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