Question

9. A room is 12 m long, 8 m broad and 4 m high. It has
two doors, each measuring 2.2 m by 1.6 m and two
windows, each measuring 2.4 m by 2.2m. Find the cost
of white washing its four walls at 7.70 per sq m.​

Answer 1

Answer:

1096.48 rs

Step-by-step explanation:

length of room = 12 m

breadth of room = 8m

height of room = 4m

so area of four walls of room = 2(l+b) × h

=2(12+8) × 4 = 2(20) ×4 = 40×4 = 160 m^2

length of door = 2.2 m

breadth of door= 1.6m

area of 1 door = lb = 2.2×1.6

= 3.52 m^2

so area of two doors = 3.52×2= 7.04 m^2

length of window= 2.4m

breadth of window= 2.2m

area of 1 window = lb = 2.4×2.2 = 5.28

so area of two windows = 5.28× 2 = 10.56

so area of four walls of room excluding area of windows and doors = 160-(7.04+10.56) = 160-17.6

= 142.4 m^2

cost of white washing= 7.70/m^2

so total cost of white washing= 7.70 × 142.4

= 1096.48 rs

so cost of white washing the walls at the rate of 7.70 per m^2 = 1096.48 rs

please mark as brainliest