Question

A wall $15m$ long. $30cm$ wide and $4m$ high is made of bricks, each measuring $22cm\times 12.5cm\times 7.5cm.$ If $\frac{1}{12}$of the total volume of the wall consists of mortar, how many bricks are there in the wall?

Answer 1

We know that volume of cuboid = length $\times$ breadth $\times$ height

So, volume of the wall $=150\times 30\times 400=18000000c{m}^3$

The quantity of mortar $=\frac{1}{12}\times 18000000=150000c{m}^3$

Hence, volume of bricks $=18000000-1500000=16500000c{m}^3$

And we know that the volume of a single brick $=22\times 12.5\times 7.5=2062.5c{m}^3$

Therefore, total number of bricks required $=\frac{totalvolumeofthebricks}{volumeofeachbrick}$

$=\frac{16500000}{2062.5}$

$=8000$ bricks