Question

$\text{A wall 15 m long, 30 cm wide and 4 m high is made of bricks, each measuring}(22cm\times 12.5cm\times 7.5cm).If\frac{1}{12}\text{of the total volume of the wall consists of mortar, how many bricks are there in the wall ?}$

Answer 1

Height of the wall = 4m = 400cm

Length of the wall = 15m = 1500cm

Width of the wall = 30cm

∴ Volume of the wall = (400 *1500 *30)cm3 = 18000000$c{m}^3$

Given that 1/12 volume of wall consist of mortar .

Volume of the wall consisting of mortar = $\frac{18000000c{m}^3}{12}$ = 1500000 $c{m}^3$

Sothat Volume of wall consisting of bricks = 18000000 - 1500000 = 16500000$c{m}^3$

Dimensions of brick l = 20 cm, b = 12.5 cm, h = 7.5 cm.

Volume of each brick = (20 x 12.5 x 7.5) cm3 = 1875 $c{m}^3$

Now the number of bricks in wall = $\frac{Volumeofthewallconsistingofbricks}{Volumeofonebrick}$

Number of bricks in wall = 16500000/1875 = 8800.

Thus, there are 8800 bricks in the wall.

Hence, the required number of bricks is 8800.