The length, breadth and height of a room are 7 m, 4 m and 9 m, respectively. Find the cost of whitewashing the walls of the room and the ceiling at the rate of ₹7.50 per m² .

₹1,695

We know that,

Area of four walls of room = 2h (l + b)

Area of ceiling = l × b

We have,

Length of room = 7 m

Breadth of room = 4 m

Height of room = 9 m

Rate of whitewashing = Rs 7.50 per m²

According to the given data,

Area of four walls of room = 2 × 9 (7 + 4) = 18 × 11 = 198 m²

Area of ceiling = 7 × 4 = 28 m²

Total area of four walls and ceiling = 198 + 28 = 226 m²

The cost of whitewashing the walls and ceiling = 226 × 7.50 = Rs.1,695