Question

How many bricks will be required to construct a wall 8 m long, 6 m high and 22.5 cm thick if each brick measures (25 cm × 11.25 cm × 6 cm)?
(a) 4800
(b) 5600
(c) 6400
(d) 5200

Answer 1

(c) 6400

Length of the wall = 8 m = 800 cm
Breadth of the wall = 6 m = 600 cm
Height of the wall = 22.5 cm

Length of the brick = 25 cm
Breadth of the brick = 11.25 cm
Height of the brick = 6 cm

∴ Number of bricks required = $\frac{\mathrm{volume}\mathrm{of}\mathrm{the}\mathrm{wall}}{\mathrm{volume}\mathrm{of}1\mathrm{brick}}$

$$\begin{gathered} =\frac{800\times 600\times 22.5}{25\times 11.25\times 6} \\ =\frac{10800000}{1687.5} \\ =6400 \end{gathered}$$