Question

a room is 9.5m long, 7.5m broad and 2.5m high. it has one door of dimensions 2m*3m and two windows each of dimensions 3.5*2m. find the cost of painting the four walls at 5.60. per square metre

Answer 1

area of room without any gap=2(l+b)h=2(9.5+7.5)2.5=85m^2
area of Door= 2×3=6m^2
area of 2 windows=3.5×2×2=14m^2
area to be painted= 85-(6+14) =20m^2
cost=20×5.60=112 rps

Answer 2

The cost of painting is ₹ 364

Given data :

Dimension of the room = 9.5m × 7.5 m × 2.5 m

Dimension of door = 2m × 3m

Dimension of the window = 3.5m × 2m

Painting cost = 5.60 rs. / m²

So,

The total surface area of the four walls = (perimeter of the floor × height) = [{2×(9.5+7.5)}×2.5] = (34×2.5) = 85 m²

So,the area of two windows = {2×(2×3.5)} = 14 m²

Area of one door = (3×2) = 6m²

Area of door + 2 windows = (6+14) = 20 m²

So,the surface area of the wall excluding doors and windows is = (85-20) = 65m²

Cost of 1 m² painting = ₹ 5.60

Cost of 65 m² painting = (5.60×65) = ₹364 (answer)