Let the side of the cube be ‘x’ units
Total surface of cuboid = 6x2 sq units
Sum of surface ares of three cubes = 3(6x2)= 18x2

Since three equal cubes are placed adjacently, length of the cube will be 3x units
Breadth = x units and height = x units
Total surface area of the cuboid = 2(lb + bh + hl) sq units

Ratio of total surface area of new cuboid to that of the surface area of the three cubes

Hence the ratio is 7:9
2 5 2