Question

The weight of a cubic meter of a certain metal is $480$ kg. It is melted and then rolled into a square bar $4m$ long. Now, an exact cube is cut from it. Find the weight of the cube.

• A. $240$ kg
• B. $80$ kg
• C. $120$ kg
• D. $60$ kg

Answer 1

The correct option is D $60$ kg

Weight of a cubic meter $=480$kg
It is melted and then rolled into a square bar $4m$ long.
$\therefore$ Volume of square bar $=4\times 1\times 1$$=4m^3$
Now, a cube is cut from it.
$\therefore$ Volume of cube $=1\times 1\times 1$$=1m^3$
Now, $4m^3$ weighs $480$kg
$\therefore 1m^3$ weighs $=\frac{480}{4}$$=60$kg