Aptitude - Area - Discussion
Discussion Forum : Area - General Questions (Q.No. 12)
12.
The length of a rectangle is halved, while its breadth is tripled. What is the percentage change in area?
Answer: Option
Explanation:
Let original length = x and original breadth = y.
Original area = xy.
| New length = | x | . |
| 2 |
New breadth = 3y.
| New area = |  |
x | x 3y |  |
= | 3 | xy. |
| 2 | 2 |
 Increase % = |
|
1 | xy x | 1 | x 100 | % |
= 50%. |
| 2 | xy |
Discussion:
25 comments Page 3 of 3.
Shashank said:
9 years ago
Assume that rectangle is 100.
Decreased by halved i.e = 50.
Increased by tripled means = 300.
So, % change is = (50 * 300)/100.
= 150.
i.e 50% more than 100.
So 50% increases.
Decreased by halved i.e = 50.
Increased by tripled means = 300.
So, % change is = (50 * 300)/100.
= 150.
i.e 50% more than 100.
So 50% increases.
(4)
Jo parker said:
8 years ago
First of all, we all know that the area of rectangle is l*b so area(old) =lb, now according to the question it is length is halved so it is l/2 and the breadth is increased by 3times so it is 3b so by area formula it product of l and b =new area=(l/2)*(3b) =3/2(lb),so in order to find the difference we have subtract the new area from the old area so new area-old area =lb/2.
So in order to convert it to percentage multiply by 100i.e (lb)/2*(100) = 50 percent.
So in order to convert it to percentage multiply by 100i.e (lb)/2*(100) = 50 percent.
Migma Tshering Tamang said:
5 years ago
Let orginal area of rectangle is 1,
Given; L=1/2(halved) and b= 3 (tripled)
now new area= 1/2 * 3.
= 1.5.
Hence, the new area increased by 1.5-1=0.5.
So, the percentage increased by 0.5/1*100=50%.
Given; L=1/2(halved) and b= 3 (tripled)
now new area= 1/2 * 3.
= 1.5.
Hence, the new area increased by 1.5-1=0.5.
So, the percentage increased by 0.5/1*100=50%.
(4)
Khadar said:
5 years ago
By using this method:
-50+300+((-50)(300)/100),
100%.
-50+300+((-50)(300)/100),
100%.
Akil said:
3 years ago
It is simple:
(L*1/2)(B*3),
LB*(3/2),
LB*(1.5).
So clearly, 50% increased.
(L*1/2)(B*3),
LB*(3/2),
LB*(1.5).
So clearly, 50% increased.
(2)
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