Question

How many bricks will be required for a wall which is 8 m long, 8 m high and 20 cm thick, if each brick measures $16 cm\times 8 cm \times 4 cm$?

Answer 1

Hint: Wall and brick both have a shape like a cuboid. In this question first, calculate the volume of a wall and volume of a brick. Then we will divide the volume of the wall by the volume of a brick. Then finally we will get the number of bricks required for a wall.

Complete step by step solution:
Given,
Length of a wall = $8 m$
Thickness of a wall = $20 cm$
Height of wall = $8 m$
 Here, the length and height of a wall are in meters so we will change it into centimeters because other units are in cm.
Therefore, Length of a wall = $8 \times 100 = 800 cm $ ($1 m = 100 cm$)
Height of a wall = $8 \times 100 = 800 cm$
Thickness of wall = $20 cm$
Volume of a wall $ = l \times b \times h$
$ = 800 \times 800 \times 20 = 12,800,000c{m^3}$
Thus, the volume of a wall is 12,800,000$c{m^3}$.
Also given,
Length of a brick = $16 cm$
Breadth of a brick = $8 cm$
Height of a brick = $4 cm$
Volume of a brick $ = l \times b \times h$
$ = 16 \times 8 \times 4 = 512c{m^3}$
Thus, the volume of a brick is $512c{m^3}$.
Let n be the number of bricks required.
$n = \dfrac{{12800000}}{{512}} = 25,000$bricks

$\therefore $ The number of bricks required for a wall = 25000.

Note:
In these types of questions, use the unitary method to find the number of bricks. Volume is the amount of space that an object or substance occupies. When we multiply the length, width, and height then we can calculate the volume of a rectangular object. SI unit of volume is Cubic meter ${m^3}$.