Question

Question 11
A mason constructs a wall of dimensions 270 cm×300 cm×350 cm with the bricks each of size $22.5cm\times 11.25cm\times 8.75cm$ 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

Thinking process- If we divide the volume of the wall except for the volume of mortar used on the wall by the volume of one brick, then we get the required number of bricks used to construct the wall.
(A) 11100
(B) 11200
(C) 11000
(D) 11300

Answer 1

Option (B) is correct.
Volume of the wall $=270\times 300\times 350=28350000c{m}^3$ $[Volumeofcuboid=length\times breadth\times height]$
Since, $\frac{1}{8}$ space of wall is covered by mortar.
Volume of the brick part of the wall $=28350000–(28350000\times \frac{1}{8})$
$=28350000–3543750=24806250c{m}^3$
Now, volume of one brick $=22.5\times 1125\times 8.75=2214.844c{m}^3$
$\therefore$ Required number of bricks $=\frac{Volumeofthebrickpartofthewall}{volumeofonebrick}$$=\frac{24806250}{2214.844}=11200\left(approx\right)$