NCERT Solutions for Class 8 Maths Exercise 2.4

NCERT Solutions for Class 8 Maths Exercise 2.4 Class 8 Maths book solutions are available in PDF format for free download. These ncert book chapter wise questions and answers are very helpful for CBSE exam. CBSE recommends NCERT books and most of the questions in CBSE exam are asked from NCERT text books. Class 8 Maths chapter wise NCERT solution for Maths Book all the chapters can be downloaded from our website and myCBSEguide mobile app for free.

NCERT solutions for Class 8 Maths Linear Equations in One Variable Download as PDF

NCERT Solutions for Class 8 Maths Linear Equations in One Variable

1. Amina thinks of a number and subtracts  from it. She multiplies the result by 8. The result now obtained is 3 times the same number she thought of. What is the number?

Ans. Let Amina think a number

According to the question,  

 

 

 

 

 

 

Hence, the number is 4.

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2. A positive number is 5 times another number. If 21 is added to both the numbers, then one of the new numbers becomes twice the other new number. What are the numbers?

Ans. Let another number be

Then positive number =

According to the question, 

 

 

 

 

Hence another number = 7 and positive number =  =35

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3. Sum of the digits of a two-digit number is 9. When we interchange the digits, it is found that the resulting new number is greater than the original number by 27. What is the two-digit number?

Ans. Let the unit place digit of a two-digit number be

Therefore, the tens place digit =

 2-digit number = 10 x tens place digit + unit place digit

 Original number =

According to the question, New number

= Original number + 27

 

 

 

 

 

 

Hence, the 2-digit number =  = 10 (9 – 6) + 6 = = 30 + 6 = 36

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NCERT Solutions for Class 8 Maths Exercise 2.4

4. One of the two digits of a two-digit number is three times the other digit. If you interchange the digits of this two-digit number and add the resulting number to the original number, you get 88. What is the original number?

Ans. Let the unit place digit of a two-digit number be

Therefore, the tens place digit =

 2-digit number = 10 x tens place digit + unit place digit

 Original number =  =

According to the question, New number + Original number = 88

 

 

 

Hence, the 2-digit number =

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NCERT Solutions for Class 8 Maths Exercise 2.4

5. Shobo’s mother’s present age is six times Shobo’s present age. Shobo’s age five years from now will be one third of his mother’s present age. What are their present age?

Ans. Let Shobo’s present age be  years.

And Shobo’s mother’s present age =  years

According to the question,  

 

 

 

 years.

Hence, Shobo’s present age = 5 years

And Shobo’s mother’s present age =  = 30 years.

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NCERT Solutions for Class 8 Maths Exercise 2.4

6. There is a narrow rectangular plot, reserved for a school, in Mahuli village. The length and breadth of the plot are in the ratio 11 : 4. At the rate `100 per meter it will cost the village panchayat`75,000 to fence the plot. What are the dimensions of the plot?

Ans. Let the length and breadth of the rectangular plot be  and  respectively.

 Perimeter of the plot =  =  = 750 m

We know that Perimeter of rectangle = 2 (length + breadth)

Therefore, according to the question,

 

 

 

 

Hence, length of rectangular plot =  = 275 m

And breadth of rectangular plot = = 100 m

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NCERT Solutions for Class 8 Maths Exercise 2.4

7. Hasan buys two kinds of cloth materials for school uniforms, shirt material that costs him `50 per meter and trouser material that costs him `90 per meter.

Ans. Let ratio between shirt material and trouser material be

The cost of shirt material =

The selling price at 12% gain =

=

=  =

The cost of trouser material =

The selling price at 12% gain =

=

=  =

According to the question,

 

  = 100 meters

Now, trouser material =  =

= 200 meters

Hence, Hasan bought 200 meters of the trouser material.

For every 2 meters of the trouser material he buys 3 meters of the shirt material. He sells the materials at 12% and 10% respectively. His total sale is `36,000. How much trouser material did he buy?

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NCERT Solutions for Class 8 Maths Exercise 2.4

8. Half of a herd of deer are grazing in the field and three fourths of the remaining are playing nearby. The rest 9 are drinking water from the pond. Find the number of deer in the herd.

Ans. Let the total number of deer in the herd be

According to question, 

 

 

 

 

 

 

 

Hence, the total number of deer in the herd is 72.

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NCERT Solutions for Class 8 Maths Exercise 2.4

9. A grandfather is ten times older than his granddaughter. He is also 54 years older than her. Find their present ages.

Ans. Let present age of granddaughter be years.

Therefore, Grandfather’s age =  years

According to question, 

 

 

 years

Hence, granddaughter’s age = 6 years and grandfather’s age =  = 60 years.

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NCERT Solutions for Class 8 Maths Exercise 2.4

10. Aman’s age is three times his son’s age. Ten years ago he was five times his son’s age. Find their present ages.

Ans. Let the present age of Amon’s son be  years.

Therefore, Aman’s age =  years

According to question,

 

 

 

  = 20 years

Hence, Aman’s son’s age = 20 years

And Aman’s age =  = 60 years

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NCERT Solutions for Class 8 Maths Exercise 2.4

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