Question

A cubic metre of copper weighing $9000$ kilograms is rolled into a square bar $9$ metres long. An exact cube is cut off from the bar. How much does it weigh?

• A. $=333\frac{1}{3}kg$
• B. $=335\frac{1}{5}kg$
• C. $=336\frac{1}{6}kg$
• D. $=332\frac{1}{3}kg$

Answer 1

The correct option is A $=333\frac{1}{3}kg$

(Area of the square end) $\times 9$
$=$ volume $=1$ cu metre
$\therefore$ Side of the square end
$==\sqrt{\frac{1}{9}}$ metres
$=\frac{1}{3}$ metres
or Volume of the cube $=\frac{1}{3}\times \frac{1}{3}\times \frac{1}{3}cub.m.$
$=\frac{1}{27}cu.m$
$\therefore$ weight of the cube $=\frac{9000}{27}kg$
$=333\frac{1}{3}kg$