How many bricks will be required to construct a wall $10$m long $4$m wide and $3$ m high, if each brick measures $25cm\times 12cm\times 8cm$?

Given the wall is of $10$m long $4$m wide and $3$ m high.

Then volume of the wall is $1000\times 400\times 300=1200,00,000$ cm${}^3$.

And volume of the brick is $25\times 12\times 8=2400$ cm${}^3$.

Now number of brick required to construct the wall is

$\frac{1200,00,000}{2400}$

$=5,000$.