Three cubes of sides 6 cm, 8 cm and 1 cm are melted to form

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Three cubes of sides 6 cm, 8 cm and 1 cm are melted to form a new cube. The surface area of the new cube is

1. 486 cm²
2. 496 cm²
3. 586 cm²
4. 658 cm²

Correct Option: A

Volume of the new cube = [(6)³ + (8)³ + (1)³] cu.cm.
= (216 + 512 + 1) cu.cm. = 729 cu.cm.
Edge of new cube = ³√729 = 9 cm
Its surface area = 6 × (edge)² = 6 × 9 × 9 = 486 sq. cm.