Two identical cubes each of volume 64 cm3 are joined together end to end. What is the surface area of the resulting cuboid?
The correct option is
D
160cm2
Let the length of a side of a cube = a cm
Given , volume of the cube ,a3=64cm3⇒a=4cm
On joining two cubes, we get a cuboid whose
Length ,l=2a cm
Breadth , b=a cm
And height , h=a cm
Now, surface area of the resulting cuboid =2(lb+bh+lh)
=2(2a×a+a×a+a×2a)
=2(2a2+a2+2a2)=2(5a2)
=10a2=10(4)2=160cm2