Question

3. The floor of a rectangular hall has a perimeter 250 m. If the cost of painting the four
walls at the rate of 10 per m’ is 15000, find the height of the hall.
Hint: Area of the four walls = Lateral surface area.]​

Answer 1

Answer :-

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

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

= 250 m.

Area of the four walls of the hall = 2h (l + b) ... (i)

Also, area of the four walls of the hall = 15000/10m²

= 1500 m² ... (ii)

From (i) and (ii),

we have 2h (l + b) = 1500

⇒ h × 250 = 1500 [ 2(l + b) = 250]

⇒ h = 1500 /250

= 6

Hence, height of the hall is 6 m