For ceiling
the area of ceiling is = 12 × 10 = 120ft²
white paint cost = 120ft²
Now the four walls cost
- area of two walls which doesn't have windows and door.
area of two wall = 2×{length × width}
= 2(8×10)
=2×80
=160ft²
- area of two walls which have 2 windows and door.
for calculating this we need to subtract that area of 2 windows and door from the total area of door.
total area of two walls was 160ft²
area of door is 22sq²
area of two windows= 2 ×(2²) = 8ft
total = 22+8 = 30ft²
Area of two walls which have 2 windows and one door = 160- 30
= 130ft²