RBSE Solutions for Class 8 Maths Chapter 15 Surface Area and Volume Ex 15.2

RBSE Solutions for Class 8 Maths Chapter 15 Surface Area and Volume Ex 15.2 is part of RBSE Solutions for Class 8 Maths. Here we have given Rajasthan Board RBSE Class 8 Maths Chapter 15 Surface Area and Volume Exercise 15.2.

Board	RBSE
Textbook	SIERT, Rajasthan
Class	Class 8
Subject	Maths
Chapter	Chapter 15
Chapter Name	Surface Area and Volume
Exercise	Exercise 15.2
Number of Questions	8
Category	RBSE Solutions

Rajasthan Board RBSE Class 8 Maths Chapter 15 Surface Area and Volume Ex 15.2

Question 1.
Dimensions of a cuboid are 60 cm. x 54 cm. x 30 cm. How many cubes of side 6 cm. can be placed in the cuboid?
Solution:
Volume of cuboid
= 60 x 54 x 30 cm.³
= 97200 cm.³
Volume of cube of side 6 cm.
= (6)³
= 216 cm.³
∴Required(RBSESolutions.com)Number of cubes

= 450 cubes

Question 2.
How many wooden logs of side 6 cm can be cut from a 3 m long, 50 cm broad and 25 cm high wooden pile.
Solution:
Volume of wooden pole
= 300 x 50 x 251 | 1 meter = 100 cm.
= 375000 cm.³
Volume of 1 cubical(RBSESolutions.com)block = 25 x 25 x 25
= 15625 cm.³
∴Required number of cubical blocks

= 24

Question 3.
Cylinder A has diameter of 14 cm and height of 7 cm and cylinder B has diameter 7 cm and height 14 cm. Without calculation tell volume of which cylinder is more? Verify the answer by calculation.

Solution:
For cylinder A
Radius of base (r) = [latex]\frac { 14 }{ 2 }[/latex] cm. = 7 cm.
Height (h) = 7 cm.
∴ Volume = πr²h
= [latex]\frac { 22 }{ 7 }[/latex] . (7)² . (7)
= 1078 cm.³

For cylinder B
Radius(RBSESolutions.com)of Base (R) = [latex]\frac { 7 }{ 2 }[/latex]cm.
Height (H) = 14 cm.
∴ Volume = πR²H
= [latex]\frac { 22 }{ 7 } .\frac { 7 }{ 2 } .\frac { 7 }{ 2 } .14[/latex]
= 539 cm.³
Hence, volume of cylinder A is 1078 – 539 = 539 cm.³ is greater than cylinder B.

Question 4.
From a cylindrical milk tanker of radius 1.5 m and length 7 m how many polythene of one liter can be packed? (1 m³ = 1000 liter)
Solution:
For tanker
Radius (r) = 1.5 meter
Height (h) = 7 meter
∴ Volume = πr²h
= [latex]\frac { 22 }{ 7 }[/latex] . (1.5) (1.5) x 7
= 49.5 m³
= 49.5 x 1000 litre
= 49500 litre
Hence, the required(RBSESolutions.com)number of polythene packs are 49500.

Question 5.
In what time a tap giving 60 litres of water per minute can fill a cylindrical tank of radius 3.5 m and depth 3 m.
Solution
For tank
Radius (r) = 3.5 meter
Depth (h) = 3 meter
∴ Volume = πr²h
= [latex]\frac { 22 }{ 7 }[/latex] x 3.5 x 3.5 x 3
= 115.5 m3
= 115.5 x 1000 litre
= 115500 liter

Question 6.
Dimensions of a cuboidal ice is 50 cm x 30 cm x 20 cm. Find its weight in kilogram. If weight of 1000 cm³ ice is 900 gram.
Solution
Volume of ice plate
= 50 x 30 x 20
= 30000 cm.³
∴Weight of ice plate
= 30000 x [latex]\frac { 900 }{ 1000 }[/latex]
= 27000 grame
= [latex]\frac { 27000 }{ 1000 }[/latex]
= 27 kg.

Question 7.
If side of a cube is doubled then,
(i) How many times its surface area will increase?
(ii) How many(RBSESolutions.com)times its volume will increase?
Solution
(i) Let a cm. be the side of cube. Then,
Surface Area S₁ = 6a² cm.²
New side = 2a cm.
.’. New Surface Area S₂ = 6 (2a)²
= 24a² cm.²
We get,

S₂ = 4 S₁
Hence, the surface(RBSESolutions.com)area of new cube will increase 4 times.
(ii) Volume V₁ = a³ cm.³

Hence, the volume will increase 8 times.

Question 8.
Volume of a cylindrical tank having 7 meter diameter is 770 cubic meter. Find height of the tank.
Solution
For tank
Radius (r) = [latex]\frac { 7 }{ 2 }[/latex] meter
Let height be h meter. Then,

∴ Height of the tank is 20 m.

We hope the given RBSE Solutions for Class 8 Maths Chapter 15 Surface Area and Volume Ex 15.2 will help you. If you have any query regarding Rajasthan Board RBSE Class 8 Maths Chapter 15 Surface Area and Volume Exercise 15.2, drop a comment below and we will get back to you at the earliest.