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 .
Answer & explanation
Correct answer: option 2
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