Question

cost of papering the four walls of a room 8 m long at the rate of 4.50 per mºs
and the cost of matting the floor at the rate of 3.50 per m2 is 140. Find the height of
room.
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Answer 1

Total cost of matting floor = Rs 91.80

rate of matting = 0.85 / m2

Then area of floor = 91.80 / 0.85 = 108 m2

But are of floor = l * b = 108 m2

given l = 12m

then b= 108/12 = 9m

Cost of papering wall = Rs 340.20

Rate of papering = 1.35 / m2

Total surface area of walls = 340.20 / 1.35 = 252 m2

But surface are of walls can be written as = 2* (l+b) * h

or 252 = 2* (l+b) * h = 2* (12+ 9 ) * h

or h = 252/ 42 = 6 m

Therefore height of the room is 6 m