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
Solution:
(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
$\therefore$ Number of bricks required $=\frac{\text { volume of the wall }}{\text { volume of } 1 \text { brick }}$
$=\frac{800 \times 600 \times 22.5}{25 \times 11.25 \times 6}$
$=\frac{10800000}{1687.5}$
$=6400$