Question

The area of four walls of a room is 420 m square if the length of the room is twice its breadth and the walls are 5 metre high find the length and breadth of the room

Answer 1

Answer:

Step-by-step explanation:

Breadth=x

Length = 2x

Area of 4 walls= 2(l+b)h

420 = 2(3x)5=30x

x=420/30=14m = Breadth

Length= 2x =28m

Answer 2

Answer:

The correct answer is:

The length of the room= 28m

The breadth of the room=14m

Step-by-step explanation:

Let us consider the breadth of the room=x

Given that  the length of the room is twice its breadth, length = 2x

Area of 4 walls= 420 $m^{2}$

Height of room=5m

Formula:

Area of 4 walls= (Area of left and right wall) + (area of front and back wall)

⇒ Area of 4 walls= 2*(l*h) + 2*(b*h)

⇒  Area of 4 walls= 2*h* (l+b)

⇒ Area of 4 walls= $2*5*(l+b)$

⇒ Area of 4 walls= $2*5*3x$

⇒ 420= $30x$

⇒$x=420/30$

⇒x=14m

The breadth of the wall (x) = 14m

The length of the wall= 2*(Breadth of the wall)

The length of the wall= 2*14 = 28 m.

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