A mason constructs a wall of dimensions 
with the bricks each of size 
and it is assumed that 
space is covered by the mortar. Then, the number of bricks used to construct the wall is
Volume of cuboid = lbh
where, l = length, b = breadth and h = height
For wall,
Length, l = 270 cm
Breadth, b = 300 cm
Height, h = 350 cm
Volume of wall = 270 × (300) × (350) = 28350000 cm3
As 
of this volume is covered by mortar, therefore 
of this volume is covered by bricks.
Volume of wall covered by bricks = 7/8 (volume of wall)
= 7/8 (2835000)
= 24806250 cm3
For one brick,
Length, l = 22.5 cm
Breadth, b = 11.25 cm
Height, h = 8.75 cm
Volume of one brick = lbh
= 22.5(11.25)(8.75) cm3
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