Question

The area of four walls of a room is \(120\, m^2\). The length of the room is twice its breadth. If the height of the room is \(4\, m\), what is the area of the floor?

• A. 40 m\(^2\)
• B. 50 m\(^2\)
• C. 60 m\(^2\)
• D. 80 m\(^2\)

Hint:

Use wall area = perimeter × height to find dimensions, then calculate floor area.

Answer 1

The Correct Option is B

Let breadth = \(b\) meters.
Then length = \(2b\) meters, height = 4 meters.
The area of four walls (perimeter × height) = \(120\, m^2\).
Perimeter of room = \(2 \times (l + b) = 2 \times (2b + b) = 6b\).
Area of four walls = perimeter × height = \(6b \times 4 = 24b\).
Given, \(24b = 120 \implies b = \frac{120}{24} = 5\, m\).
Length \(l = 2b = 2 \times 5 = 10\, m\).
Area of floor = length × breadth = \(10 \times 5 = 50\, m^2\).
Therefore, the area of the floor is \(\boxed{50\, m^2}\).