Q.If three metallic cubes with edges measuring 3 cm, 4 cm, and 5 cm are melted and recast into a new cube, the length of the edge of the new cube will be – (a) 6 cm (b) 7 cm (c) 8 cm (d) 9 cm
Answer: A
∴ The volume of the new cube
\(= (3^3 + 4^3 + 5^3)\) cubic cm
\(= 27 + 64 + 125\) cubic cm
\(= 216\) cubic cm

Let the edge length of the new cube be \(a\) cm.
Then, \(a^3 = 216\)
or, \(a^3 = 6 \times 6 \times 6\)
or, \(a = 6\)

∴ The edge length of the new cube will be \(6\) cm.
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