Answer: (3)
Let length of the room = l
Highty of the room = h
Breadth of the room = b
Given
h : l = 2 : 5
h : b = 4 : 5
∴ h : l : b = 4 : 10 : 5
Let us consider
h = 4x
l = 10x
b = 5x
Area of the four walls = 2h(l+b) = 108 m2
Area of the four walls = 2 ✕ 4x (10x + 5x)
Area of the four walls = 2 ✕ 60 x2 = 108
x2 = 108/120
The area of the floor = l ✕ b
The area of the floor = 10x ✕ 5x
The area of the floor = 50x2
The area of the floor = 50 ✕ (108/120)
The area of the floor = 45m2