Calculate the amount of materials needed to construct a

rectangular concrete floor $7\mathrm{.}6m$ by $5\mathrm{.}0m$ and $7cm$ thick. Use a

nominal mix of $1$:$3$:$6.$ The bulk density of aggregate $($sand and

stone$)$ is $1,460-1600k\frac{g}{m^3}.$ The materials normally have $30$ to

$50\%$ greater volume than the concrete mix; and $5$ to $10\%$ is

allowed for waste and spill.