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 the total area of the four walls of the room will

1) remain the same

2) decrease by 13.64%

3) decrease by 15%

4) decrease by 18.75%

5) decrease by 30%

Let the Height be of value X.

Therefore ,  Length = 3X.

                      Breadth = 2X.

Height is a common factor to all the 4 walls.

So Total Area of 4 walls (Initially) = 10 X ^ 2

Next ,

Breadth = X,

Length = 6 X

Height = X/2

So total Area now = 7 X ^2

Therefore , the total area decreases by 30 %

So Answer is 5

Hope U have got it clear.

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