Step-by-step explanation:
4 × 3 = 12 m^2
12 × 2 = 24 = floor and ceiling
3 × 2.7 = 8.1
8.1 × 2 = 16.2
4 × 2.7 = 10.8
10.8 × 2 = 21.6
total = 24+16.2+21.6 = 61.8
door = 2.1×0.85 = 1.785 m^2
window = 1.8×1.4 = 2.52
total of door and window = 1.785+2.52 = 4.305
61.8-4.305 = 57.495 m^2
1.47 × 57.495 = £84.52 (2dp)
cost = £84.52
