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Question

The lateral surface area of a cube is 144 cm2 . The length of a cuboid is 25% more than the side of the cube. The breadth of the cuboid is 5 cm less than its length and 20% less than its height. Find the total surface area of the cuboid.

A 100 cm^2 Correct Answer Incorrect Answer
B 334 cm^2 Correct Answer Incorrect Answer
C 324 cm^2 Correct Answer Incorrect Answer
D 226 cm^2 Correct Answer Incorrect Answer
E 221 cm^2 Correct Answer Incorrect Answer

Solution

Let the length of the cube be ‘a’ cm
According to the question,
4a2 = 144
=> a2 = 36
=> a = 6
Therefore, length of the cuboid = l = 1.25 × 6 = 7.5 cm
Breadth of the cuboid = b = 7.5 – 5 = 2.5 cm
Height of the cuboid = h = 2.5/0.8 = 3.125 cm
Therefore, total surface area of the cuboid = 2(lb + bh + lh) = 2 × {(7.5 × 2.5) + (2.5 × 3.125) + (7.5 × 3.125)} = 100 cm2

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