A mason constructs a wall of dimensions $270 \mathrm{~cm} \times 300 \mathrm{~cm} \times 350 \mathrm{~cm}$ with the bricks each of size $22.5
\mathrm{~cm} \times$ $11.25 \mathrm{~cm} \times 8.75 \mathrm{~cm}$ and it is assumed that $\frac{1}{8}$ space is covered by the mortar. Then, the
number of bricks used to construct the wall is
(a) 11100
(b) 11200
(c) 11000
(d) 11300
(b) Volume of the wall $=270 \times 300 \times 350=28350000 \mathrm{~cm}^{3}$
$[\because$ volume of cuboid $=$ length $\times$ breadth $\times$ height $]$
Since, $\frac{1}{8}$ space of wall is covered by mortar.
So, remaining space of wall = Volume of wall - Volume of mortar
$=28350000-3543750=24806250 \mathrm{~cm}^{3}$
Now, volume of one brick $=22.5 \times 1125 \times 8.75=2214.844 \mathrm{~cm}^{3}$
[ $\because$ volume of cuboid $=$ length $\times$ breadth $\times$ height]
$\therefore$ Required number of bricks $=\frac{24806250}{2214.844}=11200$ (approx)
Hence, the number of bricks used to construct the wall is 11200 .