Two cubes, each having a total surface area of 150 cm2, are joined together to form a cuboid. Find the total surface area of the resulting cuboid.
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Correct answer: C
Explanation
The correct answer is option 3 i.e. 250 cm2.
Total surface area (TSA) of cube = 6a2
Total surface area (TSA) of cuboid = 2(lb + bh + hl)
Given that, TSA of cube = 150 cm2
⇒ 150 = 6 × a2
⇒ a2 = 25
⇒ a = 5
Now, the side of each cube is 5 cm.
Both cubes are joined to form a cuboid so,
Length = 10 cm, breadth = 5 cm and height = 5 cm.
Therefore TSA of cuboid = 2(lb + bh + hl)
⇒ TSA = 2(10 × 5 + 5 × 5 + 10 × 5)
⇒ TSA = 2 × 125
⇒ TSA = 250
Hence the required TSA of the cuboid is 250 cm2.