Question

The cost of preparing the walls of a room, 12m long at the rate of Rs1.35/m² is Rs340.20 and the cost of matting the floor at 85 paisa/m² . Find the height of the room

Answer 1

I think,your question is as follows :
The cost of preparing the walls of the room 12m long at the rate of Rs.1.35per square meter is Rs.340.20 and the cost of matting the floor at 85 paise per m² is Rs. 91.80.find the height of the room.

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Length of the room, l = 12 m
Let the breadth be b and height be h of the room.

Then,area of the room = l × b
= 12 × b = 12b m²

Cost of matting the floor = 85 paise/m²
= Rs 0.85/m² (in rupees)

Total cost of matting the floor = cost of matting the floor per m² × area of the room
= Rs 0.85 × 12b

0.85 × 12b = 91.80
12b = 91.80/0.85
12b = 108
b = 108/12
b = 9
Breadth of the room,b = 9 m

Area of walls of the room = 2h (l + b)
= 2h (12 m + 9 m)
= 2h (21)
= 42h m²

Cost of preparing the walls = Rs 1.35 / m²
Total cost of preparing the walls = Rs 1.35 × 42h

Rs 1.35 × 42h = Rs 340.20
42h = 340.20/1.35
42h = 34020/135
42h = 252
h = 252/42
h = 6

∴ Height of the room is 6 m

Hope it helps

Answer 2

Height of the room is 6m.