Correct option is C
Given:
Perimeter of the floor = 18 m
Height of the room = 3 m
Formula Used:
Area of walls = Perimeter of the floor × Height
Solution:
Perimeter of floor = 2(l + b)
=> 2(l + b) = 18
=> l + b = 9 m
Area of walls = 2(l + b)h
=> 2 × 9 × 3
=> 54 m2