The floor of a rectangular hall has a perimeter 250 m. If the cost of painting the four walls at the rate of Rs 10 per m2 is Rs 15000, find the height of the hall.

[Hint: Area of the four walls = Lateral surface area]


Let length, breadth, and height of the rectangular hall be l m, b m, and h m respectively

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


Perimeter of the floor of hall = 2(l + b)


= 250 m


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


= 250h m2


Cost of painting per m2 area = Rs 10


Cost of painting 250h m2 area = Rs (250h × 10)


= Rs 2500h


However, it is given that the cost of paining the walls is Rs 15000


15000 = 2500h


h = 6


Therefore, the height of the hall is 6 m


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