A cuboid has dimensions 8 cm x 10 cm x 12 cm. It is cut into small cubes of side 2 cm. What is the percentage increase in the total surface area?
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Correct answer: D
Explanation
The correct answer is option 4 i.e. 386.5
l × b × h = n × (2)3
(8 × 10 × 12)/(2)3 = n
n = 120
TSA of cuboid = 2(lb + bh + hl) = 2(80 + 120 + 96) = 2 × 296 = 592 cm2
TSA of 120 cubes = 120 × 6 × (2)2 = 2880 cm2
% increase in TSA = (2880 - 592)/592 × 100 = 386.5%