Question

the ratio of a room length, width and height is 5:4:2. if in a new room, the length is increased by 40% and the width by 25%,what changes will be made in the volume of room keeping the total area of the four walls equal around the room?


A. Increased by 31.25%
B. Increased by 20.35%
C. Increased by 10%

Answer 1

Then, Finally
Length (L) = 2*6 = 12
Breadth (B) = 4/2 = 2 
Height (H) = 2/2 = 1
Total Area of Walls = 2(BH + LH) = 2*(2*1 + 12*1) = 2*(2+12) = 28

example % change in Area of four walls = (28 - 40)*100 /40 = - 30per decrease