A wall 15 m long, 30 cm wide and 4 m high is made of bricks, each measuring 22 cm × 12 cm × 7 . 5 cm . If 1 12 of the total volume of the wall consists of mortar how many bricks are there in a wall?

Given that, Length of the wall = 15 m = 1500 cm , width of the wall = 30 cm , height of the wall = 4 m = 400 cm is made of bricks. We know that, Volume of a cuboid = length × breadth × height So, the volume of the wall = 1500 × 30 × 400 = 18000000 cm 3 Given that 1 12 volume of wall consist of mortar volume of the wall consisting of mortar = 1 12 × 18000000 cm 3 = 15000000 cm 3 So that volume of the wall consisting of bricks = 18000000 - 15000000 = 16500000 cm 3 Volume of each brick = ( 22 × 12 × 7 . 5 ) = 1980 cm 3 Now the number of brick in wall = Total volume of bricks Volume of a single brick Number of bricks in wall = 16500000 1980 = 8333 (Apprx) Hence, there are 8 , 333 (approx) bricks in the wall

E M B I B E

START UP MATHEMATICS>Chapter 18 - Mensuration-II (Solid Figures)>REVIEW EXERCISES>Q 4

MEDIUM

8th CBSE

IMPORTANT

Earn 100

A hollow cylindrical pipe open at both ends is made of $2 cm$ thick iron. If the internal diameter is $50$ and the length of the pipe is $140 cm$ , find the volume of iron in it.

Important Questions on Mensuration-II (Solid Figures)

MEDIUM

8th CBSE

IMPORTANT

START UP MATHEMATICS>Chapter 18 - Mensuration-II (Solid Figures)>REVIEW EXERCISES>Q 5

A rectangular sheet of dimensions

33 cm \times 24 cm

is rolled into a cylinder so that the smaller side becomes the height of the cylinder. Find the volume of the cylinder so formed.

HARD

8th CBSE

IMPORTANT

START UP MATHEMATICS>Chapter 18 - Mensuration-II (Solid Figures)>REVIEW EXERCISES>Q 6

Two right circular cylinders of equal volumes have their height in the ratio

4 : 9

. Find the ratio of their curved surface areas.

MEDIUM

8th CBSE

IMPORTANT

START UP MATHEMATICS>Chapter 18 - Mensuration-II (Solid Figures)>REVIEW EXERCISES>Q 7

Two right circular cylinders of equal heights have their radii in the ratio

2 : 5

. Find the ratio of their curved surface area and the ratio of their volumes.

MEDIUM

8th CBSE

IMPORTANT

START UP MATHEMATICS>Chapter 18 - Mensuration-II (Solid Figures)>REVIEW EXERCISES>Q 8

A metal sheet

27 cm

long,

8 cm

broad and

1 cm

thick is melted into a cube. Find the difference between the surface areas of the two solids.

MEDIUM

8th CBSE

IMPORTANT

START UP MATHEMATICS>Chapter 18 - Mensuration-II (Solid Figures)>REVIEW EXERCISES>Q 9

A solid cubical block of fine wood costs

₹ 256

at

₹ 500 per m^{2}

. Find the length of each side and its volume.

HARD

8th CBSE

IMPORTANT

START UP MATHEMATICS>Chapter 18 - Mensuration-II (Solid Figures)>REVIEW EXERCISES>Q 10

A hollow garden roller which is $49 cm$ wide and has a girth of $176 cm$ is made of $2 cm$ thick cast iron. Find the volume of iron and weight of roller if $1 {cm}^{3}$ of iron weighs $7.5$ grams.