Question

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

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

Answer 1

The correct option is C

$6400$

Step 1: Calculate the volume of brick:

The given dimensions of the brick are $25cm\times 11.25cm\times 6cm$.

Volume of cuboid $=$length $\times$breadth $\times$ height

Volume of a brick$=25\times 11.25\times 6$

$=1687.5c{m}^3$

Step 2: Calculate the volume of wall:

The given dimensions of the wall are $8m\times 6m\times 22.5cm$

Volume of wall$=8\times 6\times 22.5$

$=800\times 600\times 22.5$ $...\left[\because 1m=100cm\right]$

$=10800000c{m}^3$

Step 3: Calculate the number of brick:

Therefore, the number of bricks needed is equal to the volume of the wall per volume of a single brick.

$\therefore$Number of bricks needed$=\frac{10800000}{1687.5}$

$=6400$

Hence, we need $6400$ bricks to build the wall, so option $\left(C\right)$ is the correct answer.