Adam wants to repaint his room. His room is 7 metres high and each wall is 10 metres wide. There are 4 windows which are 4 m2 each and a door which is 10 m2. It takes 2 litres of paint to paint a square metre of wall. Assuming Adam does not paint the ceiling, floor, windows and doors, how much litres of paint would he need?
P = Perimeter of room
H = High
Area of walls:
Aw = Perimeter of room ∙ High
Aw = P ∙ H
In this case:
P = 4 ∙ 10 = 40 m , H = 7 m
Aw = P ∙ H
Aw = 40 ∙ 7 = 280 m²
Area for painting:
Ap = Area of walls - 4 ∙ Area of windows - Area of door
Ap = 280 - 4 ∙ 4 - 10 = 280 - 16 - 10 = 280 - 26 = 254 m²
It takes 2 L / m²
He would need:
Ap ∙ 2 = 254 m² ∙ 2 L / m² = 508 L