Question

How many bricks will be needed to build a platform of $8\text{m}\times 6\text{m}\times 22.5\text{cm}$, where each brick measures $25\text{cm}\times 11.25\text{cm}\times 6\text{cm}$?

• A. $5600$
• B. $7200$
• C. $6000$
• D. $6400$

Answer 1

The correct option is D $6400$

Given:
Dimensions of each brick is $25\text{cm}\times 11.25\text{cm}\times 6\text{cm}$
Dimensions of wall is $8\text{m}\times 6\text{m}\times 22.5\text{cm}$

The volume of a cuboid is given by the production of its dimensions.
Volume of each brick:
$V_b=25\text{cm}\times 11.25\text{cm}\times 6\text{cm}$
Volume of the wall:
$V_w=800\text{cm}\times 600\text{cm}\times 22.5\text{cm}$

Since the volume of wall is taken up by bricks, number of bricks is given by:
$n=\frac{\text{Volume of wall}}{\text{Volume of one brick}}$
$n=\frac{V_w}{V_b}$
$n=\frac{800\times 600\times 22.5{\text{cm}}^3}{25\times 11.25\times 6{\text{cm}}^3}$
$n=6400$