Question

A wall of thickness $10cm$ and height $5m$ has to be built across a play ground of length $15m$. How many bricks are needed to construct the wall, if each brick has dimensions of $20cm\times 10cm\times 5cm.$?
[4 MARKS]

Answer 1

Concept: 1 Mark
Formula: 1 Mark
Application: 2 Marks

Volume of the wall across play ground is nothing but a cuboid.

Therefore, Volume of the wall
$=lbh$

$=1500\times 10\times 500c{m}^3$

$=7500000c{m}^3$

Now, each brick is a cuboid with length = 20 cm, breadth = 10 cm and height = 5 cm

So, volume of each brick = length × breadth × height

$=1000c{m}^3$

Number of bricks required

$=\frac{volumeofthewall}{volumeofeachbrick}$

$=\frac{7500000}{1000}$

$=7500$