Question

The four walls and the ceiling of a cubical room need to be painted. If the height of the room is 4 m , and painting costs ₹ 20/m2 20 / m 2 , what is the total cost of painting the room?

Answer 1

₹ 1920

Explanation:

Since the room is cubical in nature, we will find the total surface area of the room

Total surface area of the cubical room = 6L²

L is the length of one side of the room

Given

L = 4m

Total surface area of the cubical room = 6(4)²

Total surface area of the cubical room = 6×16

Total surface area of the cubical room = 96m²

If the painting costs ₹ 20/m², this means;

₹ 20 = 1m²

For the total room:

x = 96m²

Divide both expressions

20/x = 1/96

x = 20×96

x = 1920

Hence the total cost of painting the room ₹ 1920