Three solid iron cubes of edges 8 cm, 10 cm and 12 cm are melted together to make a new cube. It is observed that 496 cm3 of the melted material is lost due to improper handling. The area (in cm2) of the whole surface of the newly formed cube is:
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Correct answer: B
Explanation
The correct answer is Option 2 i.e. 1176
Volumes are:
For edge 8 cm → (a)3 = 83 = 512 cm3
For edge 10 cm → 103 = 1000 cm3
For edge 12 cm → 123 = 1728 cm3
Total volume before loss = 512 + 1000 + 1728 = 3240 cm3
the lost material = 3240 − 496 = 2744 cm3
Let edge = a
a3 = 2744
a =
Surface area = 6a2 = 6 × 142 = 6 × 196 = 1176 cm2