Three equal cubes, are placed adjacently in a row. Then the ratio of the total surface area of the cuboid formed to the sum of the total surface areas of the three cubes is :

Question

Question

This question was previously asked in

Haryana CET Previous Year Paper (Held On: 6 Nov 2022 Shift 2)

Answer 1

Given :

Three cube are placed adjacent in a row to form a cuboid.

Solution :

Let the side of cube be "a"

Three cubes are placed in a row then

Breadth of cuboid be a

Length of cuboid be 3a

Height of cuboid be a.

Sum of total surface area of three cubes :

⇒ 6a²+ 6a² + 6a²

⇒ 18a²

Total surface area of resulting cuboid :

⇒ 2 ( lb + bh + lh )

⇒ 2 ( 3 a × a + a × a + 3 a × a )

⇒ 2 ( 7a² )

⇒ 14a²

Ratio of total surface area of cuboid to that of cube :

⇒ 14a² / 18a²

⇒ 7/9

Hence the correct answer is "7 : 9".