Question

10. A wall 15 m long, 30 cm wide and 4 m high is made of bricks, each measuring
22 cm x 12.5 cm x 7.5 cm . If
of the total volume of the wall consists of mortar, how many
12
bricks are there in the wall?
Hint. Volume of bricks in the wall = {(1500x30x400) – x (1500x30x400)} cm”.
11. Find the capacity of a rectangular cistern in
cistern in litres whose dimensions
11.2 m x6 m x 5.8 m. Find the area of the iron sheet required to make the cistern.
12
are​

Answer 1

Answer:

The dimension of the wall are

Length =15m

Breadth =0.3m

Height =4m

We know that

Volume of the wall=1×b×h

By substituting the values

Volume of the wall =15×0.3×4

So we get

Volume of the wall =18 cm

3

It is given that the wall consists of 1/2 mortar

So we get

Volume of one mortar =1/12×18

By division

Volume of mortar 1.5 m

3

So the volume of all = Volume of wall -Volume of mortar

By substituting the values

Volume of wall =18−1.5

By subtraction

Volume of vall =16.5 m

3

Length =22cm=0.22 m

Breadth =12.5 cm=0.125 m

Height =7.5cm=0.075 m

We know that

Volume of one brick =1×b×h

By substituting the values

Volume of one brick =0.22×0.125×0.075

So we get

Volume of one brick =0.0020625 m

3

So the number of bricks = Volume of bricks / Volume of one brick

By substituting the values

Number of bricks =

0.0020625

16.5

So we get

Number of bricks =8000

Therefore, the number of bricks in the wall are 8000.