Question

The floor of a rectangular hall has a perimeter 250m. If the cost of panting the four walls at the rate of Rs.10 per $m^2$ is Rs.15000, find the height of the hall.

Answer 1

Let length , breadth, and height of the rectangular hall be l m, b m, and h m respectively.
Area of four walls = 2h + 2bh
= 2(l+b) h
Perimeter of the floor of hall = 2 (l+b)
= 250m
$\therefore$ Area of four walls = 2 (l+b)h=250 h $m^2$
Cost of painting per $m^2$ area = Rs 10
Cost of painting 250h $m^2$ area= $Rs.(250h\times 10)=Rs.2500h$ However, it is given that the cost of painting the walls is Rs 15000.
$\therefore$ 15000 = 2500h
h =6
Therefore, the height of the hall is 6 m.