Wallpaper 260 m long and 30 cm broad is required to cover the walls of

1.	Wallpaper 260 m long and 30 cm broad is required to cover the walls of a room.Length of the room is 7 m and its breadth is twice its height. Determine theheight of the room.
Answer» Given : Length of wallpaper = 260 m and breadth = 30 m So, Area of wallpaper = 260×30 = 7800 m2 And Length of the room is 7 m and its breadth is twice its height. Let Height of room =x , So Breadth of room = 2x And surface area of all four walls of room = 2 ( Length×Height + Breadth×Height ) , So 2 ( 7x+ 2x(x) ) = 7800 7x + 2x2= 3900 2x2+ 7x- 3900 = 0 We know quadratic formula : x =−b±b2−4ac√2ahere a= 2 , b = 7 and c = -3900 So, x =−7±72−4×2×−3900√2×2=−7±49+31200√4=−7±31249√4So, x =−7−31249√4and−7+31249√4 But we assume "x " is height of room so that can't be neagtive so we neglect negative term (x =−7−31249√4)and get x =−7+31249√4=−7+176.774=169.774=42.44 Therefore, Height of room = 42.44 m answer is 3m

Wallpaper 260 m long and 30 cm broad is required to cover the walls of a room.Length of the room is 7 m and its breadth is twice its height. Determine theheight of the room.

Answer»

Given : Length of wallpaper = 260 m and breadth = 30 m

So,

Area of wallpaper = 260×30 = 7800 m2

And

Length of the room is 7 m and its breadth is twice its height.

Let Height of room =x , So

Breadth of room = 2x

And surface area of all four walls of room = 2 ( Length×Height + Breadth×Height ) , So

2 ( 7x+ 2x(x) ) = 7800

7x + 2x2= 3900

2x2+ 7x- 3900 = 0

We know quadratic formula :

x =−b±b2−4ac√2ahere a= 2 , b = 7 and c = -3900

So,

x =−7±72−4×2×−3900√2×2=−7±49+31200√4=−7±31249√4So,

x =−7−31249√4and−7+31249√4

But we assume "x " is height of room so that can't be neagtive so we neglect negative term (x =−7−31249√4)and get

x =−7+31249√4=−7+176.774=169.774=42.44

Therefore,

Height of room = 42.44 m

answer is 3m