The length, breadth
and height of a room are in the ratio . If the breadth and height are halved while the length is doubled,
then the total area of the four walls of the room will.
a) decrease by 30%
b) decrease by 15%
c) decrease by 13.64%
d) remains the same
e) None.
a) decrease by 30%
b) decrease by 15%
c) decrease by 13.64%
d) remains the same
e) None.
Answer: Option a
ReplyDeleteExplanation:
Let the original length, breadth and height of the room be 3x, 2x and x respectively.
Therefore, the new length, breadth and height are 6x, x and x/2 respectively.
Area of four walls = (2 × length × height) + (2 × breadth × height)
Original area of four walls,
=(2×3x×x)+(2×2x×x)
=〖10x〗^2
Therefore, the new length, breadth and height are 6x, x and x/2 respectively.
New area of four walls,
=(2×6x×x2)+(2×x×x2)
=〖7x〗^2
Therefore, Area of wall decreases by
=[(10x2−7x2)÷10x2]×100
=30%