Question

How many bricks of measure 25 cm × 16 cm × 10 cm are required to make a wall of size 20 m long , 5 m high , 50 cm thick , while there are two doors of size 2 m × 1.5 m in the wall​

Answer 1

Step-by-step explanation:

Dimension of brick are =20cm×10cm×5cm

volume of 1 brick =20×10×5=1000cm

3

Dimension of wall =10m×15m×0.2m

volume of wall =10×15×0.2=30m

3

now no. of brick requried to make wall =

volumeof1brick

volumeofwall

no. of bricks =

1000m

3

30m

3

=

1000

30

×10

6

=30×10

3

[no. of bricks =30,000 bricks.]

Answer 2

Note: The breadth of the door is $\[1\,{\rm{m}}{\rm{.}}\]$

Given,

The dimensions of a brick$\[ = 25\,{\rm{cm}} \times 16\,{\rm{cm}} \times 10\,{\rm{cm}}\]$

The dimension of the wall$\[ = 20\,{\rm{m}} \times 5\,{\rm{m}} \times 50\,{\rm{cm}}\]$

The number of doors$\[ = 2\]$

The dimensions of the door$\[2\,{\rm{m}} \times 1.5\,{\rm{m}} \times 1\,{\rm{m}}\]$

Solution,

The volume of the bricks used

$\[\begin{array}{l} = 25 \times 16 \times 10\\ = 4000\,\,{\rm{c}}{{\rm{m}}^3}\end{array}\]$

The volume of the wall

$\[\begin{array}{l} = 2000 \times 500 \times 50\\ = 5 \times {10^7}\,\,{\rm{c}}{{\rm{m}}^3}\end{array}\]$

The volume of the doors

$\[\begin{array}{l} = 2 \times \left( {2\,{\rm{m}} \times 1.5\,{\rm{m}} \times 1\,{\rm{m}}} \right)\\ = \left( {2 \times 3\,} \right){{\rm{m}}^3}\\ = 6{{\rm{m}}^3}\end{array}\]$

Therefore, the number of bricks are

$\[\begin{array}{l} = \frac{{\left( {5 \times {{10}^7}} \right) - \left( {6 \times {{10}^6}} \right)}}{{4000}}\\ = 11000\end{array}\]$

Hence, the number of bricks are $\[11000.\]$