Question

a room has l=8m,b=4m,and h=4m,which is to be wall papered.it has one door of 2m*1m and one window of 1m*1m.if width of the wall paper is 50cm,find the length of the paper required to couer its four walls and ceiling. also find the cost of paper at the rate of 15rs per metre in hindi

Answer 1

Total surface area of cuboid=
2(lb+bh+hl)
Since the floor us not to be wall papered...therefore
Area of the wall paper required=
2(lb+bh+lh)-lb=
2[(8)(4)+(4)(4)+(4)(8)]-32=2(80)-32
=160-32=128

Now, the window with dimensions 1×2 and the door with dimensions 1×1 are also to be excluded.
Therefore,
Area of the wall paper required=
128-(2+1)=125m^2

Now given widhth of the wall paper is 50/100m
Therefore,
50/100×L=125
L= 250m

Now
Cost of 1m wall paper= 15rs
Therefore
Cost of 250m wall paper = 250×15=375rs