Question

The internal dimensions of a rectangular room are 6 m, 5m and 3.5m. It has two doors of size 1.2 m by 2 m and three windows of size 1m by 1.9m. The walls of the room are to be papered with a wallpaper of width 70cm. Find the cost of the paper at the rate of 6.50 per metre

Answer 1

Given Length of room = 6 m
Width of room = 5 m
And
Height of room = 3.5 m

So ,

Total surface area of room ( Where we want to stick wallpapers ) = 2 ( Length × Height + Width × Height ) , Here we do not take ( Length × Width )
As we do not stick wallpapers of the floor and on the ceiling .

So ,

Total surface area of room = 2 ( 6 × 3.5 + 5 × 3.5 ) = 2 ( 21 + 17.5 ) = 2 × 38.5 = 77 m2
And
Area of Two doors = 2 ( 1.2 × 2 ) = 2 × 2.4 = 4.8 m2
And
Area of three windows = 3 ( 1 × 1.9 ) = 3 × 1.9 = 5.7 m2
So,
Total area for wallpaper = 77 - 4.8 - 5.7 = 66.5 m2
And
Cost of wallpaper = Rs . 6.5 per m2 , So

Cost of wallpaper for this room = 66.5 × 6.5 = Rs. 432.25 ( Ans )

And If we want to find length of wallpaper used , and width = 70 cm = 0.7 m
So,
Length of wallpaper used = 66.5/0.7 = 95 m

Answer 2

Answer:

Answer is 617.50

Step-by-step explanation:

Area of wall is 2(l+b) h

2(6+5) 3.5 = 77

Less area of window and door 5.7 and 4.8

77-(5.7 + 4.8) = 77-10.5 = 66.5

Now divide area by width of wallpaper 66.5/0.7= 95

Cost of wallpaper 95*6.5 = 617.50