Question

the floor of a rectangular hall has a perimeter 250 metres. if the cost of painting the four walls at the rate of rupees 10 per metre square is 15000 find the height of the wall?

Answer 1

Perimeter = 250 metres
2 ( l + b ) = 250

Now, 
Cost = Area * Rate
15000 = Area * 10
Area = 15000 / 10
Area of the four walls = 1500 m²

Now, The area of the four walls of the hall is the curved surface area of the cuboidal hall
Curved surface area of the hall = 2 ( l +b ) * height

1500 = 250 * h
since ,perimeter = 2 ( l + b ) = 250

h = 1500 / 250
height = 6 metres.

Answer 2

Step-by-step explanation:

Let length, breadth, and height of the rectangular hall be l, b, and h 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 square meter area = Rs.10

Cost of painting 250h square meter area = Rs (250h×10) = Rs.2500h

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

15000 = 2500h

Or h = 6

Therefore, the height of the hall is 6 m.