Question:
Tick (✓) the correct answer:
How many bricks, each measuring 25 cm × 11.25 cm × 6 cm, will be needed to build a wall 8 m long, 6 m high and 22.5 cm thick?
(a) 5600
(b) 6000
(c) 6400
(d) 7200
Solution:
(c) 6400
Volume of each brick $=25 \times 11.25 \times 6=1687.5 \mathrm{~cm}^{3}$
Volume of the wall= $800 \times 600 \times 22.5=10800000 \mathrm{~cm}^{3}$
$\therefore$ No. of bricks $=\frac{10800000}{1687.5}=6400$