Question

Find the number of bricks, each measuring $25cm\times 12.5cm\times 7.5cm$ required to construct a wall $6m$ long, $5m$ high and $0.5m$ thick, while the cement and sand mixture occupies $\frac{1}{20}$ of the volume of the wall.

Answer 1

Given wall dimensions as: 6 m long, 5 m high and 0.5 m thick.

$⟹$ volume of wall $=6\times 5\times 0.5=15m^3$

Given, cement and sand mixture occupies $\frac{1}{20}$ of the volume of the wall.

Therefore, volume of the wall occupied by the bricks $=(1-\frac{1}{20})$ volume of wall $=\frac{19}{20}$ volume of the wall

$=\frac{19}{20}\times 15=14.25m^3$

Now, volume of each brick $=\frac{25}{100}m\times \frac{125}{1000}m\times \frac{75}{1000}m$

So, the number of bricks required = $\frac{\text{volume of wall}}{\text{volume of each brick}}=\frac{14.25m^3}{\frac{25}{100}m\times \frac{125}{1000}m\times \frac{75}{1000}m}=6080$

Hence, $6080$ bricks of given dimensions are required to construct the wall.