The dimensions of a room are 12.5 m by 9 m by 7 m. There are 2 doors and 4 windows in the room; each door measures 2.5 m by 1.2 m and each window 1.5 m by 1 m. Find the cost of painting the walls at Rs 3.50 per square metre.
Length of room (l) = 12.5 m
Breadth (b) = 9 m
and height (h) = 7 m
∴ Total area of walls = 2h(l+b)
=2×7[12.5+9]=14×21.5 m2
=301 m2
Area of 2 doors of 2.5 m×1.2 m
=2×2.5×1.2 m2=6 m2
and area of 4 window of 1.5 m×1 m
=4×1.5×1=6 m2
∴ Remaining area of walls = 301−(6+6)
=301−12=289 m2
Rate of painting the walls = Rs 3.50 per m2
∴ Total cost = 289×3.50=Rs 1011.50