Question 46

A cuboid has dimensions $$8 cm \times 10 cm \times 12 cm$$. It is cut into small cubes of side $$2 cm$$. What is the percentage increase in the total surface area?

Solution

Surface area of cuboid=2(8×12+12×10+8×10)=592 .

Let say it cutted into n number of small cubes.

Then according to question:

$$n×2^3=8×12×10$$

or, n=120.

So, Total surface area of all cubes

$$=120×6×2^2$$=2880.

So, percentage increase in Total surface area=((2880-592)/592)×100=386.4%.

D is correct choice.

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