Question

The total cost of painting of four walls of a square hall at Rs. 40 per sq. m. is Rs. 12000. If the hall contains 600 m³ of air, find the height of the hall.​

Answer 1

Answer:

The height of the hall is 9.375 meters

Step-by-step explanation:

The rate at which the walls of the square hall are painted, R = Rs. 40 per sq. m.

The total cost of painting the square hall, C = Rs. 12,000

The volume of air contained in the hall, V = 600 m³

The surface area of the four walls of the hall, A = C/A

∴ A = Rs. 12,000/(Rs. 40/m²) = 300 m²

Let 's' represent the length of sides of the square hall, and let 'h' represent the height of the square wall, we have;

The volume of the hall, V = s² × h

The surface area of the wall, A = 4 × s × h

Therefore, we get;

A = 300 = 4 × s × h

V = 600 = s² × h

V/A = 600/300 = 2 = s² × h/(4 × s × h) = s/4

s/4 = 2

s = 4 × 2 = 8

The side length of the square hall, s = 8 m.

From the area, A = 4 × s × h, we get;

A = 300 = 4 × 8 × h

h = 300/(4 × 8) = 9.375

The height of the hall, h = 9.375 m.