Question

three equal cubes are placed adjacently in a row. find the ratio of total surface area of the new cuboid that of the sum the surface areas of the three cubes

Answer 1

TSA of cuboid  = 2 ( 3a*a + a*a + 3a*a)
TSA of cuboid  = 2 (7a²)
TSA of cuboid  = 14a²                                                             (i)

TSA of 1 Cube = 6a²
TSA of 3 Cube = 18a²                                                             (ii)

thus ratio of TSA of Cuboid To TSA of cube will be

14a² : 18a²
or
7 : 9

Answer 2

Hope that's right .