Question

Find how much steel was actually used, if $\frac{1}{12}$ of the steel actually used was wasted in making the tank.

Answer 1

Given$:h=4.5m,r=2.1m$

Total surface area of tank $=2\pi r(r+h)$

$=2\times \frac{22}{7}\times 2.1\times (2.1+4.5)=2\times \frac{22}{7}\times 2.1\times 6.6=87.12m^2$

Let amount of steel used in making the tank $x$

Steel wasted $=\frac{x}{12}$

Given that:Amount of steel required − Amount of steel wasted = TSA of tank.

$\Rightarrow x-\frac{x}{12}$ $=87.12$

$\Rightarrow \frac{11x}{12}=87.12$

$\Rightarrow x=\frac{12}{11}\times 87.12=95.04m^2$

$\therefore 95.04m^2$ steel was used in actual while making such a tank.