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 4 of 8.
Mero baduwal said:
8 years ago
Please solve the question that what percent changes in area of rectangular if there is mistake in length and breadth by one percent.
Madhu said:
8 years ago
Increases 20% so (120/100) * (120/100) =14400/10000=144%.
44% increases.
44% increases.
Veer said:
8 years ago
This can be solved in very simple steps. It is as follow.
The area of rectangle = l * b,
Consider initial is 100 and given that 20% increase,
100----->20%--->120----->20%---->144,
(144-100) = 44.
The area of rectangle = l * b,
Consider initial is 100 and given that 20% increase,
100----->20%--->120----->20%---->144,
(144-100) = 44.
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.
ER RAJKUMAR ARYA said:
8 years ago
Let, l = b = 1 unit.
a1 = 1*1 = 1 sq.unit.
20% increase in both sides, new area a2 = 1.2*1.2 = 1.44.
i.e, % increase in area = 1.44 - 1 = .44 or 44%.
a1 = 1*1 = 1 sq.unit.
20% increase in both sides, new area a2 = 1.2*1.2 = 1.44.
i.e, % increase in area = 1.44 - 1 = .44 or 44%.
Hussain said:
8 years ago
a*(200+a)/100.
so, 20*(200+20)/100.
=44%.
so, 20*(200+20)/100.
=44%.
Puja said:
8 years ago
20 +20+20*20/100=44%.
Harmanpreet said:
7 years ago
Each side 20% increased thus 120*120/100=144,
then 144-100 =44.
then 144-100 =44.
Santhosh said:
1 decade ago
Let the original length be 100
so the increment on all sides by 20% i.e. length = 120
now calculate the area of original rectangle and new increased length's rectangle
i.e. A1 = 100*100= 10000 ; A2 = 120 * 120 = 14400
A2-A1 = 4400
so % increase in the area = 4400/100 = 44 %
so the increment on all sides by 20% i.e. length = 120
now calculate the area of original rectangle and new increased length's rectangle
i.e. A1 = 100*100= 10000 ; A2 = 120 * 120 = 14400
A2-A1 = 4400
so % increase in the area = 4400/100 = 44 %
Ram said:
1 decade ago
In a easy way.
Assume l & b = 10, 10.
Area = 10*10 = 100.
New length with 20% increase = 10*120/100 = 12.
So same as new breath with 20% increase = 12.
New area = 12*12 = 144.
Difference of both area = 44 %.
Assume l & b = 10, 10.
Area = 10*10 = 100.
New length with 20% increase = 10*120/100 = 12.
So same as new breath with 20% increase = 12.
New area = 12*12 = 144.
Difference of both area = 44 %.
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