top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

By what percentage will increased the total area of the 4 walls of the room?

0 votes
114 views

The length, breadth and height of a room are in the ratio 11 : 5 : 7.
If the breadth is doubled, length is increased by 4 times while the height is halved.
By what percentage will increased the total area of the 4 walls of the room?

posted Jun 28, 2019 by Ankur Athari

Share this puzzle
Facebook Share Button Twitter Share Button LinkedIn Share Button

2 Answers

0 votes

68.75% increase


Length- L = 11x
Breadth- B= 5x
Height- H = 7x
Area of four walls- A= LH*2+BH*2=2H(L+B)=2*7x*(11x+5x)=224*x^2
New dimensions:
Ln=4L
Bn=2B
Hn=1/2H
New area- An=2Hn(Ln+Bn)=2H*1/2*(4L+2B)=7x*(44x+10x)=378*x^2
The difference = 378x^2-224x^2=154x^2
% = 100*154/224=68.75% increase

answer Jun 28, 2019 by Hanifa Mammadov
0 votes

Room 1, length = 11, breadth = 5, height = 7
Room2 length = 44, breadth = 10 , height = 3,5
Let us calculate the total area for the two rooms,
Room 1
(7x11x2) + ( 7 x5x2) = 224
Room 2
( 10x3,5x2) + (44x3,5x2) = 378
Then the percentage is calculated as follows:
(378 - 224 ) / 224 = 0,6875 or 68,75 %

answer Jun 30, 2019 by anonymous



Similar Puzzles
0 votes

The length of a rectangle exceeds its width by 5m. If the width is increased by 1m and the length is decreased by 2m, the area of the new rectangle is 4 sq.m less than the area of the original rectangle. Find the dimensions of the original rectangle.

0 votes

The price of a product was reduced by 35% last year.
During this year by what percentage should it be increased to bring it back to the original price of the last year?

+1 vote

If the price off a dress was cut by 20% for a sale, by what percentage off the sale price must it be increased by to resell it at the original price?

Puzzle Image

+1 vote

The length and breadth of a square are increased by 305 and 20% respectively. The area of the rectangle so formed exceeds the area of the square by what percentage ?

...