Explanation:
I just answered that. so, here again :
all we need to do is find the surface area, deduct windows and door areas.
that gives us the m² to be covered, which we have to multiply by $12.50 to get the total price.
the house surface area is like for a box, but we don't care about the top and the bottom. only about the walls.
the "box" is 18 m × 14 m × 4 m.
so, the front and the back walls are each
18m × 4 m = 72 m²
both front and back : 2×72 = 144 m²
each side wall is
14m × 4m = 56 m²
both sides : 2×56 = 112 m²
now for the deductions.
each window is
1.5 × 2 = 3 m²
both windows : 2×3 = 6 m²
the door is
1 × 2.5 = 2.5 m²
so, the total area to "side" is
144 + 112 - 6 - 2.5 = 247.5 m²
to side 247.5 m² it costs
247.5 × 12.5 = $3,093.75