Correct Answer - Option 2 : 600 cm
2
Given:
Three solid iron cubes of edges 6 cm, 7 cm, and 8 cm.
71 cm3 of the melted material is lost due to improper handling.
Concept:
The volume of cube = a3
The total surface area of cube = 6a2
Where a = side
When a figure melted together to make a new figure then the volume is equal.
Explanation:
Volume of three solid cube = Volume of a new cube
V = 63 + 73 + 83 = 216 + 343 + 512 = 1071 cm3
(∵ 71 cm3 of the melted material is lost due to improper handling)
So volume of new cube (a3) = 1071 - 71 = 1000 cm3
⇒ a = 10 cm
Total surface area of volume = 6a2 = 6 × 102
∴ The total surface area of new cube is 600 cm2.