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
The area of the four walls is length*height*2 + breadth*height*2
Initial area = 3*1*2 + 2*1*2 = 10
Final area = 6*1/2*2 + 1*1/2*2 = 7
So, the area decreased by 30%
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