Question

Three cubes of metal whose edges are 3 cm , 4 cm and 5 cm are melted to form a new cube whose side is

• A. 4 cm
• B. 5 cm
• C. 6 cm
• D. 12 cm

Answer 1

The correct option is C 6 cm

Given the three cubes of metal whose side are 3 cm , 4 cm and 5 cm

Then volume of cube who side 3 cm=$(3{)}^3=27c{m}^3$

And volume of cube who side 4 cm=$(4{)}^3=64c{m}^3$

And volume of cube who side 5 cm=$(5{)}^3=125c{m}^3$

Total volume of melted cube=27+64+125=216$c{m}^3$

Then the side of new cube=$a^3=216$

$\Rightarrow a=6cm$