Question

The length breadth and height of a room are in the ratio 3 : 2 : 1. If the breadth and height are halved while the length is doubled, then total area of the four walls of the room will (1) Remain the same (2) Decrease by 30% (3) Decrease by 15% (4) Decrease by 18.75%​

Answer 1

Let us consider the room with

Length (l) = 3x

Breadth (b) = 2x

Height = 1x

Area of the walls (A) = 2(l + b) × h

A = 2(3x + 2x) × 1x

A = 10x2 sq. unit.

Now

l1 = 6x

b1 = x

h1 = x/2

Nwe area (A1) = 2(6x + x) (x/2)

A1 = 7x2

% decrease in the area of walls = 30%

Answer 2

Answer:

Let us consider the room with

Length (l) = 3x

Breadth (b) = 2x

Height = 1x

Area of the walls (A) = 2(l + b) × h

A = 2(3x + 2x) × 1x

A = 10x2 sq. unit.

Now

l1 = 6x

b1 = x

h1 = x/2

Nwe area (A1) = 2(6x + x) (x/2)

A1 = 7x2

% decrease in the area of walls = 30%

Step-by-step explanation:

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