The length, breadth and height of a room are in the ratio 3 :2: J. If the breadth and height are halved while the length is doubled, ·then the total area of the four walls of the room will

Options

A. remain the same
B. decrease by 13.64%
C. decrease by 15%
D. decrease by 18.75%

Answer

D

Explanation

Total area of four walls of a room `=2h(l+b)`
Let the height of the room be x.
The breadth = 2x and length =3x
`"Area"_((1)) =2x(2x=3x)=10x^2`
`"Area"_((2))=2xxx/2((2x)/2+3x xx2)=7x^2`
`:.` Area of 4 walls decreases by 30%.