A solid cube made of steel is melted and recast such that its length breadth and height changes as 1...........

Quant (SSC) Percentage

A solid cube made of steel is melted and recast such that its length, breadth and height changes as +10%, +10%, -20%. What is the percentage change in surface area of this cube?

No Change

+1%

+2%

-1%

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Explanation:

Let the surface area of each side of initial cube be 100.
The surface area of the resulting cuboid would be given by 2(lb + bh + lh)
So, ?lb = 100 + 10% ---> 110 + 10% ---> 121
?bh = 100 + 10% ---> 110 - 20% ---> 88
?lh = 100 + 10% ---> 110 - 20% ---> 88
Therefore, new surface area = 2 (121 + 88 + 88) = 594
% change in surface area = a * (−6/600) ∗ 100 = −1 (Initial surface area = 6 sides x 100 = 600)
The percentage change in surface area of this cube is -1%.

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