The floor of a rectangular hall has a perimeter 250 m. If the cost of

1.	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.]
Answer» Perimeter of a rectangle room = 250 m = 2(l + b) Cost of Painting = Rs. 15000 For Rs. 10, 1 sq.m. For Rs.15000 … ? = \(\frac{15000}{10}\) = 1500m2 Area of four walls = Lateral surface area Lateral surface area of rectangle = 1500 m² 2h(l + b) = 1500 h × 2(l + b) = 1500 h × 250 = 1500 h = \(\frac{1500}{250}\) ∴ h = 6 m

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.]

Answer»

Perimeter of a rectangle room = 250 m

= 2(l + b)

Cost of Painting = Rs. 15000

For Rs. 10, 1 sq.m.

For Rs.15000 … ? = \(\frac{15000}{10}\)

= 1500m2

Area of four walls = Lateral surface area

Lateral surface area of rectangle = 1500 m²

2h(l + b) = 1500

h × 2(l + b) = 1500

h × 250 = 1500

h = \(\frac{1500}{250}\)

∴ h = 6 m