Answer:
The surface area of the cuboid is 42 sq.cm.
Step-by-step explanation:
The cuboid is made of 3 unit cubes like the one to its left
Surface area of cube =
Where a is the side of cube
We are given that surface area of cube is 18 sq.cm.
So, 
Now these 3 cubes are joined together to form cuboid
So, Length of cuboid =
Breadth of cuboid = 
Height of cuboid =
Surface area of cuboid =
Hence the surface area of the cuboid is 42 sq.cm.