Math, asked by sudhanaik909, 10 months ago

give 10sums on comparing quantities.small one​

Answers

Answered by dhaldankar0
1

Answer:

Question 1.

Express the following in decimal form:

(a) 12%

(b) 25%

Solution:

(a) 12% = \frac { 12 }{ 100 } = 0.12

(b) 25% = \frac { 25 }{ 100 } = 0.25

Question 2.

Evaluate the following:

(a) 20% of 400

(b) 12\frac { 1 }{ 2 }% of 625

Solution:

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q2

Question 3.

If 20% of x is 25, then find x.

Solution:

20% of x = 25

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q3

Hence x = 125

Question 4.

Express the following as a fraction

(a) 35%

(b) 64%

Solution:

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q4

Question 5.

Express the following into per cent

(а) 1\frac { 3 }{ 5 }

(b) 2 : 5

Solution:

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q5

Question 6.

There are 24% of boys in a school. If the number of girls is 456, find the total number of students in the school.

Solution:

Let the total number of students be 100.

Number of boys = 24% of 100 = \frac { 24 }{ 100 } × 100 = 24

Number of girls = 100 – 24 = 76

⇒ If number of girls is 76, then total number of students = 100

⇒ If Number of girls is 1, then total number of students = \frac { 100 }{ 76 }

If Number of girls is 456, then total number of students = \frac { 100\times 456 }{ 76 } = 600

Hence, the total number of students in the school = 600

Question 7.

The cost of 15 articles is equal to the selling price of 12 articles. Find the profit per cent.

Solution:

Let CP of 15 articles be ₹ 100

CP of 1 article = ₹ \frac { 100 }{ 15 }

SP of 12 articles = ₹ 100

SP fo 1 article = ₹ \frac { 100 }{ 12 }

SP > CP

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q7

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q7.1

Hence, profit = 25%

Question 8.

An article is marked at ₹ 940. If it is sold for ₹ 799, then find the discount per cent.

Solution:

MP = ₹ 940

SP = ₹ 799

Discount = MP – SP = 940 – 799 = ₹ 141

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q8

Hence, discount = 15%

Question 9.

A watch was bought for ₹ 2,700 including 8% VAT. Find its price before the VAT was added.

Solution:

Cost of watch including VAT = ₹ 2,700

Let the initial cost of the watch be ₹ 100

VAT = 8% of ₹ 100 = ₹ 8

Cost of watch including VAT = ₹ 100 + ₹ 8 = ₹ 108

If cost including VAT is ₹ 108, then its initial cost = ₹ 100

If cost including VAT is ₹ 1, then its initial cost = ₹ \frac { 100 }{ 108 }

If cost including VAT is ₹ 2,700, then its initial cost = ₹ \frac { 100 }{ 108 } × 2700 = ₹ 2500

Hence, the required cost = ₹ 2,500

Question 10.

Find the amount if ₹ 2,000 is invested for 2 years at 4% p.a. compounded annually.

Solution:

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q10

Comparing Quantities NCERT Extra Questions for Class 8 Maths Q10.1

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