Question

The length, breadth and height of room are in the ratio of 5:3:1 and the room contains 960m³ of air . What is the cost of plastering its walls, floor and ceiling at Rs. 30 per m²?

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Answer 1

Rs. 22,080.

Explanation:

Let the height be x m then the breadth is 3x and the length 5x m.

x * 3x * 5x = 960

15x^3 = 960

x^3 = 64

x = ∛ 64 = 4m.

Therefore the height is 4m, the breadth = 12 m and the length = 20m.

So the area of all the surfaces

= 2 * short wall + 2 * long wall + floor + ceiling

= 2 *4*12 + 2*4*20 + 12*20 + 12*20

= 96 + 160 + 240 + 240

= 736 m^2.

Cost plastering = 736 * 30 = Rs. 22,080