Question

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

Answer 1

The dimension of the wall are
Length $=15m$
Breadth $=0.3m$
Height $=4m$

We know that

Volume of the wall$=1\times b\times h$

By substituting the values

Volume of the wall $=15\times 0.3\times 4$

So we get

Volume of the wall $=18c{m}^3$

It is given that the wall consists of $1/2$ mortar

So we get

Volume of one mortar $=1/12\times 18$

By division

Volume of mortar $1.5m^3$

So the volume of all = Volume of wall -Volume of mortar

By substituting the values

Volume of wall $=18-1.5$

By subtraction

Volume of vall $=16.5m^3$

Length $=22cm=0.22m$

Breadth $=12.5cm=0.125m$

Height $=7.5cm=0.075m$

We know that

Volume of one brick $=1\times b\times h$

By substituting the values

Volume of one brick $=0.22\times 0.125\times 0.075$

So we get

Volume of one brick $=0.0020625m^3$

So the number of bricks = Volume of bricks / Volume of one brick

By substituting the values

Number of bricks $=\frac{16.5}{0.0020625}$

So we get

Number of bricks $=8000$

Therefore, the number of bricks in the wall are $8000$.