Question

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

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

Answer 1

The correct option is C $6400$

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

Volume of a cuboid is given by the production of it's dimensions.
Volume of each brick:
$V_b=25cm\times 11.25cm\times 6cm$
Volume of the wall:
$V_w=800cm\times 600cm\times 22.5cm$

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