Aptitude - Area - Discussion
Discussion Forum : Area - General Questions (Q.No. 4)
4.
The percentage increase in the area of a rectangle, if each of its sides is increased by 20% is:
Answer: Option
Explanation:
Let original length = x metres and original breadth = y metres.
Original area = (xy) m2.
| New length = |  |
120 | x |  m |
= | |
6 | x | m. |
| 100 | 5 |
| New breadth = | |
120 | y | m |
= | |
6 | y | m. |
| 100 | 5 |
| New Area = | |
6 | x x | 6 | y | m2 |
= | |
36 | xy | m2. |
| 5 | 5 | 25 |
The difference between the original area = xy and new-area 36/25 xy is
= (36/25)xy - xy
= xy(36/25 - 1)
= xy(11/25) or (11/25)xy
 Increase % = |
|
11 | xy x | 1 | x 100 | % |
= 44%. |
| 25 | xy |
Video Explanation: https://youtu.be/I3jLjLPn1W4
Discussion:
74 comments Page 5 of 8.
Lexinah said:
1 decade ago
What if it says each side of a square not rectangle is increased by 15%?
What is the percentage area increase in its area?
What is the percentage area increase in its area?
Kadhal said:
4 years ago
@All.
My Question is How they assume both l and b equal to 100, in rectangle l and b they never in equal size, right?
My Question is How they assume both l and b equal to 100, in rectangle l and b they never in equal size, right?
(10)
Ratul sinha said:
9 years ago
Let each side 100.
Area 100 * 100,
Increased area 120 * 120,
(14400-10000) ÷ 10000 = .44,
0.44 * 100 = 44%.
Area 100 * 100,
Increased area 120 * 120,
(14400-10000) ÷ 10000 = .44,
0.44 * 100 = 44%.
Shashank said:
9 years ago
Increased percentage is 20%.
that means 120%.
For both sides, 120/100 * 120/100 = 144/100.
i.e 44% more than 100.
that means 120%.
For both sides, 120/100 * 120/100 = 144/100.
i.e 44% more than 100.
Rahul said:
1 decade ago
Let us supoose l=10, b=10 area=l*b=10*10=100
n aftr inc l=12 , b=12 area=l*b=12*12=144
144-100=44%ans
n aftr inc l=12 , b=12 area=l*b=12*12=144
144-100=44%ans
Ravi said:
9 years ago
The rational number with recurring decimal expansion 0.12 is __________.
Can anyone answer the question?
Can anyone answer the question?
Mhbkhb said:
1 decade ago
Taking 100*100 is not correct method. Because if we take 100*100 it will bcom a square but not rectangle.
Rozenelle said:
1 decade ago
If the answer is 44% it is a square not a rectangle, if it is a rectangle the correct answer is 32%.
Vaibhav said:
5 years ago
Simple trick for such problems is. If increase by x% we can calculate by the formula.
x(x+200)%100.
x(x+200)%100.
(2)
UDAY KINGS said:
8 years ago
Take side = a.
So, a increased by 20 so a = 120/100.
Area of square = a^2.
120/100*120/100 = 44.
So, a increased by 20 so a = 120/100.
Area of square = a^2.
120/100*120/100 = 44.
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